Potatoes having improved quality characteristics and methods for their production

Abstract

Potato plants which exhibit reduced levels of .alpha. glucan L-type tuber phosphorylase (GLTP) or .alpha. glucan H-type tuber phosphorylase (GHTP) enzyme activity within the potato tuber are provided. The conversion of starches to sugars in potato tubers, particularly when stored at temperatures below 7.degree. C., is reduced in tubers exhibiting reduced GLTP or GHTP enzyme activity. Reducing cold-sweetening in potatoes allows for potato storage at cooler temperatures, resulting in prolonged dormancy, reduced incidence of disease, and increased storage life. Methods for producing potato plants which produce tubers exhibiting reduced GLTP or GHTP enzyme activity are also provided. Reduction of GLTP or GHTP activity within the potato tuber may be accomplished by such techniques as suppression of gene expression using homologous antisense RNA, the use of co-suppression, regulatory silencing sequences, chemical and protein inhibitors, or the use of site-directed mutagenesis or the isolation of alternative alleles to obtain GLTP or GHTP variants with reduced starch affinity or activity.

Description

FIELD OF THE INVENTION

The invention relates to the inhibition of the accumulation of sugars in potatoes by reducing the level of .alpha. glucan L-type tuber phosphorylase or .alpha. glucan H-type tuber phosphorylase enzyme activity in the potato plant.

BACKGROUND OF THE INVENTION

Plant stresses caused by a wide variety of factors including disease, environment, and storage of potato tubers (Solanum tuberosum) represent major determinants of tuber quality. Dormancy periods between harvesting and sprouting are critical to maintaining quality potatoes. Processing potatoes are usually stored between 7 and 12.degree. C. Cold storage at 2 to 6.degree. C., versus storage at 7 to 12.degree. C., provides the greatest longevity by reducing respiration, moisture loss, microbial infection, heating costs, and the need for chemical sprout inhibitors (Burton, 1989). However, low temperatures lead to cold-induced sweetening, and the resulting high sugar levels contribute to an unacceptable brown or black color in the fried product (Coffin et al., 1987, Weaver et al., 1978). The sugars that accumulate are predominantly glucose, fructose, and sucrose. It is primarily the glucose and fructose (reducing sugars) that react with free amino groups when heated during the various cooking processes such as frying via the Maillard reaction, resulting in the formation of brown pigments (Burton, 1989, Shallenberger et al., 1959). Sucrose produces a black colouration when fried due to caramelization and charring. The ideal reducing sugar content is generally accepted to be 0.1% of tuber fresh weight with 0.33% as the upper limit and higher levels of reducing sugars are sufficient to cause the formation of brown and black pigments that results in an unacceptable fried product (Davies and Viola, 1992). Although the accumulation of reducing sugars can be slowed in higher temperature (7 to 12.degree. C.) storage, this increases microbial infection and the need to use sprout inhibitors. Given the negative environmental and health risks associated with chemical use, development of pathogens resistant to pesticides, and the fact that use of current sprout inhibitors may soon be prohibited, a need exists for potato varieties that can withstand stress and long-term cold storage without the use of chemicals, without the accumulation of reducing sugars, and with greater retention of starch.

Carbohydrate metabolism is a complex process in plant cells. Manipulation of a number of different enzymatic processes may potentially affect the accumulation of reducing sugars during cold storage. For example, inhibition of starch breakdown would reduce the buildup of free sugar. Other methods may also serve to enhance the cold storage properties of potatoes through reduction of sugar content, including the resynthesis of starch using reducing sugars, removal of sugars through glycolysis and respiration, or conversion of sugars into other forms that would not participate in the Maillard reaction. However, many of the enzymatic processes are reversible, and the role of most of the enzymes involved in carbohydrate metabolism is poorly understood. The challenge remains to identify an enzyme that will deliver the desired result, achieve function at low temperatures, and still retain the product qualities desired by producers, processors, and consumers.

It has been suggested that phosphofructokinase (PFK) has an important role in the cold-induced sweetening process (Kruger and Hammond, 1988, ap Rees et al., 1988, Dixon et al., 1981, Claassen et al., 1991). ap Reese et al. (1988) suggested that cold treatment had a disproportionate effect on different pathways in carbohydrate metabolism in that glycolysis was more severely reduced due to the cold-sensitivity of PFK. The reduction in PFK activity would then lead to an increased availability of hexose-phosphates for sucrose production. It was disclosed in European Patent 0438904 (Burrell et al., Jul. 31, 1991) that increasing PFK activity reduces sugar accumulation during storage by removing hexoses through glycolysis and further metabolism. A PFK enzyme from E. coli was expressed in potato tubers and the report claimed to increase PFK activity and to reduce sucrose content in tubers assayed at harvest. However it has been shown that pyrophosphate:fructose 6-phosphate phosphotransferase (PFP) remains active at low temperatures (Claassen et al., 1991). PFP activity can supply fructose 6-phosphate for glycolysis just as PFK can, since the two enzymes catalyse the same reaction. Therefore, the efficacy of this strategy for improving cold storage quality of potato tubers remains in doubt. Furthermore, removal of sugars through glycolysis and further metabolism would not be a preferred method of enhancing storage properties of potato tubers because of the resultant loss of valuable dry matter through respiration.

It has also been suggested that ADPglucose pyrophosphorylase (ADPGPP) has an important role in the cold-induced sweetening process. It was disclosed in International Application WO 94/28149 (Barry, et al., filed May 18, 1994) that increasing ADPGPP activity reduces sugar accumulation during storage by re-synthesising starch using reducing sugars. An ADPGPP enzyme from E. coli was expressed in potato tubers under the control of a cold-induced promoter and the report claimed to increase ADPGPP activity and lower reducing sugar content in tubers assayed at harvest and after cold temperature storage. However, this strategy does not eliminate starch catabolism but instead increases the rate of starch resynthesis. Thus, catabolism of sugars through glycolysis and respiration occurs and re-incorporation into starch is limited. Up regulation of ADPGPP would not be a preferred method of enhancing storage properties of potato tubers because of the resultant loss of valuable dry matter through respiration. Again, a method involving the reduction of catabolism of starch would be preferable as dry matter would be retained.

The degradation of starch is believed to involve several enzymes including .alpha.-amylase (endoamylase), .beta.-amylase (exoamylase), amyloglucosidase, and .alpha.-glucan phosphorylase (starch phosphorylase). By slowing starch catabolism, accumulation of reducing sugars should be prevented and the removal of sugars through glycolysis and further metabolism would be minimized.

Three different isozymes of .alpha. glucan phosphorylase have been described. The tuber L-type .alpha.1,4 glucan phosphorylase (EC 2.4.1.1) isozyme (GLTP) (Nakano and Fukui, 1986) has a low affinity for highly branched glucans, such as glycogen, and is localized in amyoplasts. The monomer consists of 916 amino acids and sequence comparisons with phosphorylases from rabbit muscle and Escherichia coli revealed a high level of homology, 51% and 40% amino acids, respectively. The nucleotide sequence of the GLTP gene and the amino acid sequence of the GLTP enzyme are shown in SEQ ID NO: 1 and SEQ ID NO: 2, respectively. The H-type tuber .alpha.-glucan phosphorylase isozyme H (GHTP) (Mori et al., 1991) has a high affinity for glycogen and is localized in the cytoplasm. The gene encodes for 838 amino acids and shows 63% sequence homology with the tuber L-type phosphorylase but lacks the 78-residue insertion and 50-residue amino-terminal extension found in the L-type polypeptide. The nucleotide sequence of the GHTP gene and the amino acid sequence of the GHTP enzyme are shown in SEQ ID NO: 3 and SEQ ID NO: 4, respectively. A third isozyme has been reported (Sonnewald et al., 1995) that consists of 974 amino acids and is highly homologous to the tuber L-type phosphorylase with 81% identity over most of the polypeptide. However, the regions containing the transit peptide and insertion sequence are highly diverse. This isozyme is referred to as the leaf L-type phosphorylase since the mRNA accumulates equally in leaf and tuber, whereas the mRNA of the tuber L-type phosphorylase accumulates strongly in potato tubers and only weakly in leaf tissues. The tuber L-type phosphorylase is mainly present in the tubers and the leaf L-type phosphorylase is more abundunt in the leaves (Sonnewald et al., 1995). The nucleotide sequence of the leaf L-type phosphorylase gene and the amino acid sequence of the leaf L-type phosphorylase enzyme are shown in SEQ ID NO: 5 and SEQ ID NO: 6, respectively.

The role of the various starch degrading enzymes is not clear, however, and considerable debate has occurred over conflicting results. For example, reduced expression of the leaf L-type phosphorylase (Sonnewald et al., 1995) had no significant influence on starch accumulation. Sonnewald et al. (1995) reported that constitutive expression of an antisense RNA specific for the leaf L-type gene resulted in a strong reduction of .alpha. glucan phosphorylase L-type activity in leaf tissue, but had no effect in potato tuber tissue. Since the antisense repression of the .alpha. glucan phosphorylase activity had no significant influence on starch accumulation in leaves of transgenic potato plants, the authors concluded that starch breakdown was not catalysed by phosphorylases. Considering the high level of sequence homology between identified .alpha. glucan phosphorylase isozymes, a similar negative response would be expected with the H-type (GHTP) and L-type tuber (GLTP) isozymes.

In view of the foregoing, there remains a need for potato plants which produce tubers exhibiting reduced conversion of starches to sugars during propagation and during storage at ambient and reduced temperatures, particularly at temperatures below 7.degree. C.

SUMMARY OF THE INVENTION

The inventors have found that surprisingly, reduction of the level of .alpha. glucan L-type tuber phosphorylase (GLTP) or .alpha. glucan H-type tuber phosphorylase (GHTP) enzyme activity within the potato tuber results in a substantial reduction in the accumulation of sugars in the tuber during propagation and storage, relative to wildtype potatoes, particularly at storage temperatures below 10.degree. C., and specifically at 4.degree. C. It is remarkable that, given the complexity of carbohydrate metabolism in the tuber, reduction in the activity of a single enzyme is effective in reducing sugar accumulation in the tuber. The inventors' discovery is even mere surprising in light of the previously discussed work of Sonnewald et al. (1995) wherein it was reported that reduced expression of the leaf L-type phosphorylase had no significant influence on starch accumulation in leaves of potato plants.

The present invention provides tremendous commercial advantages. Tubers in which cold-induced sweetening is inhibited or reduced may be stored at cooler temperatures without producing high levels of reducing sugars in the tuber which cause unacceptable darkening of fried potato products. Cold storage of tubers storage results in longer storage life, prolonged dormancy by limiting respiration and delaying sprouting, and lower incidence of disease.

Reduction in GLTP or GHTP activity in potato plants and tubers can be accomplished by any of a number of known methods, including, without limitation, antisense inhibition of GLTP or GHTP mRNA, co-suppression, site-directed mutagenesis of wildtype GLTP or GHTP genes, chemical or protein inhibition, or plant breeding programs.

Thus, in broad terms, the invention provides modified potato plants having a reduced level of .alpha. glucan L-type tuber phosphorylase (GLTP) or .alpha. glucan H-type tuber phosphorylase (GHTP) activity in tubers produced by the plants, relative to that of tubers produced by an unmodified potato plant. In a preferred embodiment, the invention provides a potato plant transformed with an expression cassette having a plant promoter sequence operably linked to a DNA sequence which, when transcribed in the plant, inhibits expression of an endogenous GLTP gene or GHTP gene. As will be discussed in detail hereinafter, the aforementioned DNA sequence may be inserted in the expression cassette in either a sense or antisense orientation. Potato plants of the present invention could have reduced activity levels of either one of GLTP or GHTP independently, or could have reduced activity levels of both GLTP and GHTP.

As discussed above, the inventors have found that reduction of activity levels of GLTP or GHTP enzymes in potato plants results in potato tubers in which sugar accumulation, particularly over long storage periods at temperatures below 10.degree. C., is reduced. Therefore, the invention further extends to methods for reducing sugar production in tubers produced by a potato plant comprising reducing the level of activity of GLTP or GHTP in the potato plant. In a preferred embodiment, such methods involve introducing into the potato plant an expression cassette having a plant promoter sequence operably linked to a DNA sequence which, when transcribed in the plant, inhibits expression of an endogenous GLTP gene or GHTP gene. As above, the DNA sequence may be inserted in the expression cassette in either a sense or antisense orientation.

As described in detail in the examples herein, improvements in cold-storage characteristics have been observed in the potato variety Desiree transformed by the methods of the present invention. A direct measure of improved cold-storage characteristics is a reduction in the level of GLTP or GHTP enzyme activity detected in potatoes after harvest and cold-storage. Transformed potato varieties have been developed wherein the total .alpha. glucan phosphorylase activity measured as imol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of plants stored at 4.degree. C. for 189 days is as much as 70% lower than the total .alpha. glucan phosphorylase activity in tubers of untransformed plants stored under the same conditions.,

Another relatively direct measure of improved cold-storage characteristics is a reduction in sweetening of potatoes observed after a period of cold-storage. Transformed potato varieties have been developed wherein the sum of the concentrations of glucose and fructose in tubers stored at 4.degree. C. for 91 days is 39% lower than the sum of the concentrations of glucose and fructose in tubers of an untransformed plant stored under the same conditions.

Yet another measure of improved cold-storage characteristics, demonstrating a practical advantage of the present invention, is a reduction in darkening of a potato chip during processing (cooking). As discussed hereinbefore, the accumulation of sugars in potatoes during cold-storage contributes to unacceptable darkening of the fried product. Reduced darkening upon frying can be quantified as a measure of the reflectance, or chip score, of the fried potato chip. Techniques for measuring chip scores are discussed herein. Transformed potato varieties of the present invention have been developed wherein the chip score for tubers of plants stored at 4.degree. C. for 124 days was as much as 89% higher than the chip scores for tubers of untransformed plants stored under the same conditions.

By reducing GLTP and/or GHTP activity in tubers of potato plants, thereby inhibiting sugar accumulation during cold-temperature storage, the present invention allows for storage of potatoes at cooler temperatures than would be possible with wildtype potatoes of the same cultivar. As discussed above, storage of potatoes at cooler temperatures than those traditionally used could result in increased storage life, increased dormancy through reduced respiration and sprouting, and reduced incidence of disease. It will be apparent to those skilled in the art that such additional benefits also constitute improved cold-storage characteristics and may be measured and quantified by known techniques.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings illustrating embodiments of the invention:

FIG. 1 is a schematic diagram of the tuber L-type .alpha. glucan phosphorylase antisense sequence inserted into the pBI121 transformation vector;

FIG. 2 is a schematic diagram of the tuber H-type .alpha. glucan phosphorylase antisense sequence inserted into the pBI121 transformation vector;

FIG. 3 shows the basic structure of the three isolated isoforms of glucan phosphorylase. The transit peptide (TS) and insertion sequence (IS) are characteristic of the L-type phosphorylases and are not found in the H-type phosphorylase. The percentages indicate the nucleic acid sequence homologies between the isoforms;

FIG. 4 is a schematic diagram of carbohydrate interconversions in potatoes (Sowokinos 1990);

FIG. 5 is a comparison of the amino acid sequences of the three isoforms of phosphorylase found in potato for the region targeted by the antisense GLTP construct used in the Examples herein. Highlighted amino acids are identical. The leaf L-type .alpha. glucan phosphorylase amino acid sequence is on top (amino acids 21-238 of SEQ ID NO: 6), the tuber L-type .alpha. glucan phosphorylase amino acid sequence is in the middle (amino acids 49-266 of SEQ ID NO: 2), and tuber H-type .alpha. glucan phosphorylase amino acid sequence is on the bottom (amino acids 46-264 of SEQ ID NO: 4);

FIG. 6A and 6B are a comparison of the nucleotide sequences of the three isofornns of phosphorylase found in potato for the region targeted by the antisense GLTP construct used in the Examples herein. Highlighted nucleotides are identical. The leaf L-type .alpha. glucan phosphorylase nucleotide sequence is on top (nucleotides 389-1045 of SEQ ID NO: 5), the tuber L-type .alpha. glucan phosphorylase nucleotide sequence is in the middle (nucleotides 338-993 of SEQ ID NO: 1), and tuber H-type .alpha. glucan phosphorylase nucleotide sequence is on the bottom (nucleotides 147-805 of SEQ ID NO: 3);

FIG. 7 is a northern blot of polyadenylated RNA isolated from potato tubers of wild type and lines 3,4,5, and 9 transformed with the tuber L-type .alpha. glucan phosphorylase. The blot was probed with a radiolabelled probe specific for the tuber L-type .alpha. glucan phosphorylase;

FIG. 8 is a northern blot of total RNA isolated from potato tubers of wild type and lines 1 and 2 transformed with the H-type .alpha.-glucan phosphorylase. The blot was probed with a radio labelled probe specific for the H-type .alpha. glucan phosphorylase;

FIG. 9 shows the fried product obtained from (A) wild type and tuber L-type .alpha. glucan phosphorylase transformants (B) ATL1 (C) ATL3 (D) ATL4 (E) ATL5 (F) ATL9 field grown tubers following 86 days storage at 4.degree. C. ("ATL"=antisense tuber L-type transformant);

FIG. 10 shows the activity gel and western blot of L-type and H-type isozymes of .alpha. 1,4 glucan phosphorylase extracted from wild type tubers and tubers transformed with the antisense construct for the L-type isoform; and

FIG. 11 shows the activity gel and western blot of L-type and H-type isozymes of .alpha. 1,4 glucan phosphorylase extracted from wild type tubers and transformed with the antisense construct for the H-type isoform .

DESCRIPTION OF THE PREFERRED EMBODIMENT

Potato plants having a reduced level of .alpha. glucan L-type tuber phosphorylase (GLTP) or .alpha. glucan H-type tuber phosphorylase (GHTP) activity in tubers produced by the plants relative to that of tubers produced by unmodified potato plants are provided. In the exemplified case, reduction in .alpha. glucan phosphorylase activity is accomplished by transforming a potato plant with an expression cassette having a plant promoter sequence operably linked to a DNA sequence which, when transcribed in the plant, inhibits expression of an endogenous GLTP gene or GHTP gene. Although, in the exemplified case, the DNA sequence is inserted in the expression cassette in the antisense orientation, a reduction in .alpha. glucan phosphorylase activity can be achieved with the DNA sequence inserted in the expression cassette in either a sense or antisense orientation.

1 Homology Dependent Silencing

The control of gene expression using sense or antisense gene fragments is standard laboratory practice and is well documented in the literature. Antisense and sense suppression are both gene sequence homology-dependent phenomena that may be described as "homology-dependent silencing" phenomena.

A review of scientific research articles published during 1996 reveals several hundred reports of homology-dependent silencing in transgenic plants. The mechanisms underlying homology-dependent silencing are not fully understood, but the characteristics of the phenomena have been studied in many plant genes and this body of work has been extensively reviewed (Meyer and Saedler 1996, Matzke and Matzke 1995, Jorgensen 1995, Weintraub 1990, Van der Krol et al. 1988) Homology-dependent silencing appears to be a general phenomenon that may be used to control the activity of many endogenous genes. Examples of genes exhibiting reduced expression after the introduction of homologous sequences include dihydroflavanol reductase (Van der Krol 1990), polygalacturonidase (Smith et al 1990), phytoene synthase (Fray and Grierson 1993), pectinesterase (Seymour et al. 1993), phenylalanine ammonia-lyase (De Carvalho et al. 1992), .beta.-1,3-glucanase (Hart et al. 1992), chitinase (Dorlhac et al. 1994) nitrate reductase (Napoli et al. 1990), and chalcolne synthase (14). Transformation of Russet Burbank potato plants with either sense- or antisense- constructs of the potato leafroll virus coat protein gene has been reported to coinfer resistance to potato leafroll virus infection (Kawchuk et al. 1991). The transfer of a homologous sense or antisense sequence usually generates transformants with reduced endogenous gene expression. As discussed in detail in the examples herein, transformed potato plants exhibiting phenotypes indicating reduced GLTP or GHTP expression can be readily identified. In the antisense suppression technique, a gene construct or expression cassette is assembled which, when inserted into a plant cell, results in expression of an RNA which is of complementary sequence to the mRNA produced by the target gene. It is theorized that the complementary RNA sequences form a duplex thereby inhibiting translation to protein. The theory underlying both sense and antisense inhibition has been discussed in the literature, including in Antisense Research and Applications (CRC Press, 1993) pp. 125-148. The complementary sequence may be equivalent in length to the whole sequence of the target gene, but a fragment is usually sufficient and is more convenient to work with. For instance, Cannon et al. (1990) reveals that an antisense sequence as short as 41 base pairs is sufficient to achieve gene inhibition. U.S. Pat. No. 5,585,545 (Bennett et al., Dec. 17, 1996) describes gene inhibition by an antisense sequence of only 20 base pairs. There are many examples in the patent literature of patents including descriptions and claims to methods for suppressing gene expression through the introduction of antisense sequences to an organism, including, for example, U.S. Pat. No. 5,545,815 (Fischer et al., Aug. 13, 1996) and U.S. Pat. No. 5,387,757 (Bridges et al., Feb. 7, 1995).

Sense-sequence homology-dependent silencing is conducted in a similar manner to antisense suppression, except that the nucleotide sequence is inserted in the expression cassette in the normal sense orientation. A number of patents, including U.S. Pat. Nos. 5,034,323, 5,231,020 and 5,283,184, disclose the introduction of sense sequences leading to suppression of gene expression.

Both forms of homology-dependent silencing, sense- and antisense-suppression, are useful for accomplishing the down-regulation of GLTP or GHTP of the present invention. It is recognized in the art that both techniques are equally useful strategies for gene suppression. For instance, both U.S. Pat. No. 5,585,545 (Bennett et al., Dec. 17, 1996) and U.S. Pat. No. 5,451,514 (Boudet et al., Sep. 15, 1995) claim methods for inhibiting gene expression or recombinant DNA sequences useful in methods for suppressing gene expression drawn to both sense- and antisense-suppression techniques.

2 Alternate Techniques for Reducing GHTP and/or GLTP Activity in Tubers

Although homology-dependent silencing is a preferred technique for the down-regulation of GLTP or GHTP in potato plants of the present invention, there are several commonly used alternative strategies available to reduce the activity of a specific gene product which will be understood by those skilled in the art to bear application in the present invention. Insertion of a related gene or promoter into a plant can induce rapid turnover of homologous endogenous transcripts, a process referred to as co-suppression and believed to have many similarities to the mechanism responsible for antisense RNA inhibition (Jorgensen, 1995; Brusslan and Tobin, 1995). Various regulatory sequences of DNA can be altered (promoters, polyadenylation signals, post-transcriptional processing sites) or used to alter the expression levels (enhancers and silencers) of a specific MRNA. Another strategy to reduce expression of a gene and its encoded protein is the use of ribozymes designed to specifically cleave the target mRNA rendering it incapable of producing a fully functional protein (Hasseloff and Gerlach, 1988). Identification of naturally occurring alleles or the development of genetically engineered alleles of an enzyme that have been identified to be important in determining a particular trait can alter activity levels and be exploited by classical breeding programs (Oritz and Huaman, 1994). Site-directed mutagenesis is often used to modify the activity of an identified gene product. The structural coding sequence for a phosphorylase enzyme can be mutagenized in E. coli or another suitable host and screened for reduced starch phosphorolysis. Alternatively, naturally occurring alleles of the phosphorylase with reduced affinity and/or specific activity may be identified. Additionally, the activity of a particular enzyme can be altered using various inhibitors. These procedures are routinely used and can be found in text books such as Sambrook et al. (1989).

3 Variants of GLTP and GHTP Enzymes and Sequences Used for Homology Dependent Silencing

As discussed in the background of the invention, and in greater detail by Nakano et al. (1986), Mori et al. (1991), and Sonnewald et al. (1990), there are three known .alpha. glucan phosphorylase isozymes that occur in potato plants. The present invention relates to down-regulation of the GLTP and/or GHTP isozymes. While it is believed that the GLTP and GHTP genes of all known commercial potato varieties are substantially identical, it is expected that the principles and techniques of the present invention would be effective in potato plants having variant full length polynucleotide sequences or subsequences which encode polypeptides having the starch catabolizing enzymatic activity of the described GLTP and GHTP enzymes. The terms "GLTP" and "GHTP", as used herein and in the claims, are intended to cover the variants described above. The foregoing variants may include GLTP and GHTP nucleotide sequence variants that differ from those exemplified but still encode the same polypeptide due to codon degeneracy, as well as variants which encode proteins capable of recognition by antibodies raised against the GLTP and GHTP amino acid sequences set forth in SEQ ID NO's. 2 and 4.

Similarly, those skilled in the art will recognize that homology dependent silencing of GLTP and/or GHTP in potato plants may be accomplished with sense or antisense sequences other than those exemplified. First, the region of the GLTP or GHTP cDNA sequence from which the antisense sequence is derived is not essential. Second, as described hereinabove, the length of the antisense sequence used may vary considerably. Further, the sense or antisense sequence need not be identical to that of the target GLTP or GHTP gene to be suppressed. As described in the Examples herein, the inventors have observed that transformation of potato plants with antisense DNA sequences derived from the GHTP gene not only substantially suppresses GHTP gene activity, but causes some degree of suppression of GLTP gene activity. The GHTP and GLTP genes antisense sequences have 56.8% sequence identity. The sequence identity between the GLTP antisense sequence and the corresponding leaf type .alpha. glucan phosphorylase squence described by Sonnewald et al. (1990) is 71.3%. In the inventors' research to date, the same phenomenon of cross-downregulation has not been observed when potato plants are transformed with antisense DNA sequences derived from the GLTP gene. Nevertheless, these results clearly indicate that absolute sequence identity between the target endogenous .alpha. glucan phosphorylase gene and the recombinant DNA is not essential given that GLTP activity was suppressed by an antisense sequence having about 57% sequence identity with the target GLTP sequence.

Thus, it will be understood by those skilled in the art that sense or antisense sequences other than those exemplified herein and other than those having absolute sequence identity with the target endogenous GLTP or GHTP gene will be effective to cause suppression of the endogenous GLTP or GHTP gene when introduced into potato plant cells. Useful sense or antisense sequences may differ from the exemplified antisense sequences or from other sequences derived from the endogenous GHTP or GLTP gene sequences by way of conservative amino acid substitutions or differences in the percentage of matched nucleotides or amino acids over portions of the sequences which are aligned for comparison purposes.

U.S. Pat. No. 5,585,545 (Bennett et al., Dec. 17, 1996) provides a helpful discussion regarding techniques for comparing sequence identity for polynucleotides and polypeptides, conservative amino acid substitutions, and hybridization conditions indicative of degrees of sequence identity. Relevant parts of that discussion are summarized herein.

Percentage of sequence identity for polynucleotides and polypeptides may be determined by comparing two optimally aligned sequences over a comparison window, wherein the portion of the polynucleotide or polypeptide sequence in the comparison window may include additions or deletions (i.e., gaps) as compared to the reference sequence (which does not comprise additions or deletions) for optimal alignment of the two sequences. The percentage is calculated by: (a) determining the number of positions at which the identical nucleic acid base or amino acid residue occurs in both sequences to yield the number of matched positions; (b) dividing the number of matched positions by the total number of positions in the window of comparison; and, (c) multiplying the result by 100 to yield the percentage of sequence identity. Optimal alignment of sequences for comparison may be conducted by computerized implementations of known algorithms (e.g., GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group (GCG), 575 Science Dr., Madison, Wis., or BlastN and BlastX available from the National Center for Biotechnology Information), or by inspection.

Polypeptides which are substantially similar share sequences as noted above except that residue positions which are not identical may differ by conservative amino acid changes. Conservative amino acid substitutions refer to the interchangeability of residues having similar side chains. For example, a group of amino acids having aliphatic side chains is glycine, alanine, valine, leucine, and isoleucine; a group of amino acids having aliphatic-hydroxyl side chains is serine and threonine; a group of amino acids having amide-containing side chains is asparagine and glutamine; a group of amino acids having aromatic side chains is phenylalanine, tyrosine, and tryptophan; a group of amino acids having basic side chains is lysine, arginine, and histidine; and a group of amino acids having sulfur-containing side chains is cysteine and methionine.

Another indication that nucleotide sequences are substantially identical is if two molecules specifically hybridize to each other under stringent conditions. Stringent conditions are sequence dependent and will be different in different circumstances. Generally, stringent conditions are selected to be about 10.degree. C. lower than the thermal melting point (T.sub.m) for the specific sequence at a defined ionic strength and pH. The T.sub.m is the temperature (under defined ionic strength and pH) at which 50% of the target sequence hybridizes to a perfectly matched probe. The T.sub.m of a hybrid, which is a function of both the length and the base composition of the probe, can be calculated as described in Sambrook et al. (1989). Typically, stringent conditions for a Southern blot protocol involve washing at 65.degree. C. with 0.2.times.SSC. For preferred oligonucleotide probes, washing conditions are typically about at 42.degree. C. in 6.times.SSC.

4 General Methods

Various methods are available to introduce and express foreign DNA sequences in plant cells. In brief, the steps involved in preparing antisense .alpha. glucan phosphorylase cDNAs and introducing them into a plant cell include: (1) isolating mRNA from potato plants and preparing cDNA from the mRNA; (2) screening the cDNA for the desired sequences; (3) linking a promoter to the desired cDNAs in the opposite orientation for expression of the phosphorylase genes; (4) transforming suitable host plant cells; and (5) selecting and regenerating cells which transcribe the inverted sequences.

In the exemplified case, DNA derived from potato GLTP and GHTP genes is used to create expression cassettes having a plant promoter sequence operably linked to an antisense DNA sequence which, when transcribed in the plant, inhibits expression of an endogenous GLTP gene or GHTP gene. Agrobacterium tumefaciens is used as a vehicle for transmission of the DNA to stem explants of potato plant shoots. A plant regenerated from the transformed explants transcribes the antisense DNA which inhibits activity of the enzyme.

The recombinant DNA technology described herein involves standard laboratory techniques that are well known in the art and are described in standard references such as Sambrook et al. (1989). Generally, enzymatic reactions involving DNA ligase, DNA polymerase, restriction endonucleases and the like are performed according to the manufacturer's specifications.

5 Preparation of GHTP and GLTP cDNA

cDNA is prepared from isolated potato tuber mRNA by reverse transcription. A primer is annealed to the mRNA, providing a free 3' end that can be used for extension by the enzyme reverse transcriptase. The enzyme engages in the usual 5'-3' elongation, as directed by complementary base pairing with the mRNA template to form a hybrid molecule, consisting of a template RNA strand base-paired with the complementary cDNA strand. After degradation of the original mRNA, a DNA polymerase is used to synthesize the complementary DNA strand to convert the single-stranded cDNA into a duplex DNA.

After DNA amplification, the double stranded cDNA is inserted into a vector for propagation in E. coli. Typically, identification of clones harbouring the desired cDNA's would be performed by either nucleic acid hybridization or irmunological detection of the encoded protein, if an expression vector is used. In the exemplified case, the matter is simplified in that the DNA sequences of the GLTP and GHTP genes are known, as are the sequences of suitable primers (Brisson et al., 1990; Fukui et al., 1991). The primers used hybridize within the GLTP and GHTP genes. Thus, it is expected that the amplified cDNA's prepared represent portions of the GLTP and GHTP genes without further analysis. E. coli transformed with pUC19 plasmids carrying the phosphorylase DNA insert were detected by color selection. Appropriate E. coli strains transformed with plasmids which do not carry inserts grow as blue colonies. Strains transformed with pBluescript plasmids carrying inserts grow as white colonies. Plasmids isolated from transformed E. coli were sequenced to confirm the sequence of the phosphorylase inserts.

6 Vector Construction

The cDNAs prepared can be inserted in the antisense or sense orientation into expression cassette in expression vectors for transformation of potato plants to inhibit the expression of the GLTP and/or GHTP genes in potato tubers.

As in the exemplified case, which involves antisense suppression, the desired recombinant vector will comprise an expression cassette designed for initiating transcription of the antisense cDNAs in plants. Additional sequences are included to allow the vector to be cloned in a bacterial or phage host.

The vector will preferably contain a prokaryote origin of replication having a broad host range. A selectable marker should also be included to allow selection of bacterial cells bearing the desired construct. Suitable prokaryotic selectable markers include resistance to antibiotics such ampicillin.

Other DNA sequences encoding additional functions may also be present in the vector, as is known in the art. For instance, in the case of Agrobacterium transformations, T-DNA sequences will also be included for subsequent transfer to plant chromosomes.

For expression in plants, the recombinant expression cassette will contain in addition to the desired sequence, a plant promoter region, a transcription initiation site (if the sequence to be transcribed lacks one), and a transcription termination sequence. Unique restriction enzyme sites at the 5' and 3' ends of the cassette are typically included to allow for easy insertion into a pre-existing vector. Sequences controlling eukaryotic gene expression are well known in the art.

Transcription of DNA into mRNA is regulated by a region of DNA referred to as the promoter. The promoter region contains sequence of bases that signals RNA polymerase to associate with the DNA, and to initiate the transcription of mRNA using one of the DNA strands as a template to make a corresponding complimentary strand of RNA. Promoter sequence elements include the TATA box consensus sequence (TATAAT), which is usually 20 to 30 base pairs (bp) upstream (by convention -30 to -20 bp relative to the transcription start site) of the transcription start site. In most instances the TATA box is required for accurate transcription initiation. The TATA box is the only upstream promoter element that has a relatively fixed location with respect to the start point.

The CAAT box consensus sequence is centered at -75, but can function at distances that vary considerably from the start point and in either orientation.

Another common promoter element is the GC box at -90 which contains the consensus sequence GGGCGG. It may occur in multiple copies and in either orientation.

Other sequences conferring tissue specificity, response to environmental signals, or maximum efficiency of transcription may also be found in the promoter region. Such sequences are often found within 400 bp of transcription initiation size, but may extend as far as 2000 bp or more. In heterologous promoter/structural gene combinations, the promoter is preferably positioned about the same distance from the heterologous transcription start site as it is from the transcription start site in its natural setting. However, some variation in this distance can be accommodated without loss of promoter function.

The particular promoter used in the expression cassette is not critical to the invention. Any of a number of promoters which direct transcription in plant cells is suitable. The promoter can be either constitutive or inducible.

A number of promoters which are active in plant cells have been described in the literature. These include the nopaline synthase (NOS) and octopine synthase (OCS) promoters (which are carried on tumour-inducing plasmids of Agrobacterium tumefaciens), the caulimovirus promoters such as the cauliflower mosaic virus (CaMV) 19S and 35S and the figwort mosaic virus 35S-promoters, the light-inducible promoter from the small subunit of ribulose-1,5-bis-phosphate carboxylase (ssRUBISCO, a very abundant plant polypeptide), and the chlorophyll a/b binding protein gene promoter, etc. All of these promoters have been used to create various types of DNA constructs which have been expressed in plants; see, e.g., PCT WO8402913.

The CaMV 35S promoter used in the Examples herein, has been shown to be highly active and constitutively expressed in most tissues (Bevan et al., 1986). A number of other genes with tuber-specific or enhanced expression are known, including the potato tuber ADPGPP genes, large and small subunits (Muller et al., 1990). Other promoters which are contemplated to be useful in this invention include those that show enhanced or specific expression in potato tubers, that are promoters normally associated with the expression of starch biosynthetic or modification enzyme genes, or that show different patterns of expression, for example, or are expressed at different times during tuber development. Examples of these promoters include those for the genes for the granule-bound and other starch synthases, the branching enzymes (Blennow et al., 1991; WO 9214827; WO 9211375), disproportionating enzyme (Takaha et al., 1993) debranching enzymes, amylases, starch phosphorylases (Nakano et al., 1989; Mori et al., 1991), pectin esterases (Ebbelaar et al., 1993), the 40 kD glycoprotein; ubiquitin, aspartic proteinase inhibitor (Stukerlj et al., 1990), the carboxypeptidase inhibitor, tuber polyphenol oxidases (Shahar et al., 1992; GenBank Accession Numbers M95196 and M95197), putative trypsin inhibitor and other tuber cDNAs (Stiekema et al., 1988), and for amylases and sporamins (Yoshida et al., 1992; Ohta et al., 1991).

In addition to a promoter sequence, the expression cassette should also contain a transcription termination region downstream of the structural gene to provide for efficient termination. The termination region may be obtained from the same gene as the promoter sequence or may be obtained from different genes. In the exemplified case the nopaline synthase NOS 3' terminator sequence (Bevan et al. 1983) was used.

Polyadenylation sequences are also commonly added to the vector construct if the mRNA encoded by the structural gene is to be efficiently translated (Alber and Kawasaki, 1982). Polyadenylation is believed to have an effect on stabilizing mRNAs. Polyadenylation sequences include, but are not limited to the Agrobacterium octopine synthase signal (Gielen et al., 1984) or the nopaline synthase signal (Depicker et al., 1982).

The vector will also typically contain a selectable marker gene by which transformed plant cells can be identified in culture. Typically, the marker gene encodes antibiotic resistance. These markers include resistance to G418, hygromycin, bleomycin, kanamycin, and gentamycin. In the exemplified case, the marker gene confers resistance to kanamycin. After transforming the plant cells, those cells containing the vector will be identified by their ability to grow in a medium containing the particular antibiotic.

7 Transformation of Plant Cells

Although in the exemplified case potato plant shoot stem explants were transformed via inoculation with Agrobacterium tumefaciens carrying the antisense sequence linked to a binary vector, direct transformation techniques which are known in the art can also be used to transfer the recombinant DNA. The vector can be microinjected directly into plant cells. Alternatively, nucleic acids may be introduced to the plant cell by high velocity ballistic penetration by small particles having the nucleic acid of interest embedded within the matrix of the particles or on the surface. Fusion of protoplasts with lipid-surfaced bodies such as minicells, cells or lysosomes carrying the DNA of interest can be used. The DNA may also be introduced into plant cells by electroporation, wherein plant protoplasts are electroporatecd in the presence of plasmids carrying the expression cassette.

In contrast to direct transformation methods, the exemplified case uses vectored transformation using Agrobacterium tumefaciens. Agrobacterium tumefaciens is a Gram-negative soil bacteria which causes a neoplastic disease known as crown gall in dicotyledonous plants. Induction of tumours is caused by tumour-inducing plasmids known as Ti plasmids. Ti plasmids direct the synthesis of opines in the infected plant. The opines are used as a source of carbon and/or nitrogen by the Agrobacteria.

The bacterium does not enter the plant cell, but transfers only part of the Ti plasmid, a portion called T-DNA, which is stably integrated into the plant genome, where it expresses the functions needed to synthesize opines and to transform the plant cell. Vir (virulence) genes on the Ti plasmid, outside of the T-DNA region, are necessary for the transfer of the T-DNA. The vir region, however, is not transferred. In fact, the vir region, although required for T-DNA transfer, need not be physically linked to the T-DNA and may be provided on a separate plasmid.

The tumour-inducing portions of the T-DNA can be interrupted or deleted without loss of the transfer and integration functions, such that normal and healthy transformed plant cells may be produced which have lost all properties of tumour cells, but still harbour and express certain parts of T-DNA, particularly the T-DNA border regions. Therefore, modifieds Ti plasmids, in which the disease causing genes have been deleted, may be used as vectors for the transfer of the sense and antisense gene constructs of the present invention into potato plants (see generally Winnacker, 1987).

Transformation of plants cells with Agrobacterium and regeneration of whole plants typically involves either co-cultivation of Agrobacterium with cultured isolated protoplasts or transformation of intact cells or tissues with Agrobacterium. In the exemplified case, stem explants from potato shoot cultures are transformed with Agrobacterium.

Alternatively, cauliflower mosaic virus (CaMV) may be used as a vector for introducing sense or antisense DNA into plants of the Solanaceae family. For instance, U.S. Pat. No. 4,407,956 (Howell, Oct. 4, 1983) teaches the use of cauliflower mosaic virus DNA as a plant vehicle.

8 Selection and Regeneration of Transformed Plant Cells

After transformation, transformed plant cells or plants carrying the antisense or sense DNA must be identified. A selectable marker, such as antibiotic resistance, is typically used. In the exemplified case, transformed plant cells were selected by growing the cells on growth medium containing kanamycin. Other selectable markers will be apparent to those skilled in the art. For instance, the presence of opines can be used to identify transformants if the plants are transformed with Agrobacterium.

Expression of the foreign DNA can be confirmed by detection of RNA encoded by the inserted DNA using well known methods such as Northern blot hybridization. The inserted DNA sequence can itself be identified by Southern blot hybridization or the polymerase chain reaction, as well (See, generally, Sambrook et al. (1989)).

Generally, after it is determined that the transformed plant cells carry the recombinant DNA, whole plants are regenerated. In the exemplified case, stem and leaf explants of potato shoot cultures were inoculated with a culture of Agrobacterium tumefaciens carrying the desired antisense DNA and a kanamycin marker gene. Transformants were selected on a kanamycin-containing growth medium. After transfer to a suitable medium for shoot induction, shoots were transferred to a medium suitable for rooting. Plants were then transferred to soil and hardened off. The plants regenerated in culture were transplanted and grown to maturity under greenhouse conditions.

9 Analysis of GHTP and GLTP Activity Levels in Transformed Tubers

Following regeneration of potato plants transformed with antisense DNA sequences derived from the GHTP and GLTP genes, the biochemistry of transformed tuber tissue was analyzed several ways. The in vitro activity of .alpha. glucan phosphorylase in the phosphorolytic direction was assayed according to the methods of Steup (1990) (Table 1). The activity of the enzyme in the synthetic direction and the amount of enzyme protein were compared after electrophoretic separation of the enzyme isoforms on a glycogen-containing, polyacrylamide gel (FIG. 7). Starch synthesis by the tuber L-type and H-type isoforms was determined by iodine staining of the gel after incubation with glucose-1-phosphate and a starch primer (Steup, 1990). Western analysis was performed by blotting the protein from an identical unincubated native gel to nitrocellulose and probing with polyclonal antibodies specific for tuber type L and type H glucan phosphorylase isoforms. Levels of reducing sugars (glucose and fructose) in tuber tissues were quantified by HPLC (Tables 2, 3 and 4). The extent of Maillard reaction, which is proportional to the concentration of reducing sugars in tubers was examined by determining chip scores after frying (Table 5 and FIG. 9).

10Definitions

As used herein and in the claims, the term:

"about three months", "about four months" and "about six months" refer, respectively, to periods of time of three months plus or minus two weeks, four months plus or minus two weeks, and six months plus or minus two weeks;

"antisense orientation" refers to the orientation of nucleic acid sequence from a structural gene that is inserted in an expression cassette in an inverted manner with respect to its naturally occurring orientation. When the sequence is double stranded, the strand that is the template strand in the naturally occurring orientation becomes the coding strand, and vice versa;

"chip score" of a tuber means the reflectance measurement recorded by an Agtron model E-15-FP Direct Reading Abridged Spectrophotometer (Agtron Inc. 1095 Spice Island Drive #100, Sparks Nevada 89431) of a center cut potato chip fried at 205.degree. F. in soybean oil for approximately 3 minutes until bubbling stops;

"cold storage" or "storage at reduced temperature" or variants thereof, shall mean holding at temperatures less than 10.degree. C., that may be achieved by refrigeration or ambient temperatures;

"endogenous", as it is used with reference to .alpha. glucan phosphorylase genes of a potato plant, shall mean a naturally occurring gene that was present in the genome of the potato plant prior to the introduction of an expression cassette carrying a DNA sequence derived from an .alpha. glucan phosphorylase gene;

"expression" refers to the transcription and translation of a structural gene so that a protein is synthesized;

"heterologous sequence" or "heterologous expression cassette" is one that originates from a foreign species, or, if from the same species, is substantially modified from its original form;

"improved cold-storage characteristics" includes, without limitation, improvements in chip score and reduction in sugar accumulation in tubers measured at harvest or after a period of storage below 10.degree. C., and further includes improvements, advantages and benefits which may result from the storage of potatoes at cooler temperatures than those traditionally used, such as, without limitation, increased storage life of potatoes, increased dormancy through reduced respiration and sprouting of potatoes, and reduced incidence of disease. Unless further qualified by a specific measure or test, an improvement in a cold-storage characteristic refers to a difference in the described characteristic relative to that in a control, wildtype or unmodified potato plant;

"modified" or variants thereof, when used to describe potato plants or tubers, is used to distinguish a potato plant or tuber that has been altered from its naturally occurring state through: the introduction of a nucleotide sequence from the same or a different species, whether in a sense or antisense orientation, whether by recombinant DNA technology or by traditional cross-breeding methods including the introduction of modified structural or regulatory sequences; modification of a native nucleotide sequence by site-directed mutagenesis or otherwise; or the treatment of the potato plant with chemical or protein inhibitors. An "unmodified" potato plant or tuber means a control, wildtype or naturally occurring potato plant or tuber that has not been modified as described above;

"nucleic acid sequence" or "nucleic acid segment" refer to a single or double-stranded polymer of deoxyribonucleotide or ribonucleotide bases read from the 5' to the 3' end. It includes both self-replicating plasmids, infectious polymers of DNA or RNA and non-functional DNA or RNA;

"operably linked" refers to functional linkage between a promoter and a second sequence, wherein the promoter sequence initiates transcription of RNA corresponding to the second sequence;

"plant " includes whole plants, plant organs (e.g. leaves, stems, roots, etc.) seeds and plant cells;

"promoter" refers to a region of DNA upstream from the structural gene and involved in recognition and binding RNA polymerase and other proteins that initiate transcription. A "plant promoter" is a promoter capable of initiating transcription in plant cells;

"reduced activity" or variants thereof, when used in reference to the level of GLTP or GHTP enzyme activity in a potato tuber includes reduction of GLTP or GHTP enzyme activity resulting from reduced expression of the GLTP or GHTP gene product, reduced substrate affinity of the GLTP or GHTP enzyme, and reduced catalytic activity of the GLTP or GHTP enzyme;

"reduced" or variants thereof, may be used herein with reference to, without limitation, activity levels of GLTP or GHTP enzyme in potato tubers, accumulation of sugars in potato tubers and darkening of potato chips upon frying. Unless further qualified by a specific measure or test, reduced levels or reduced activity refers to a demonstrable statistically significant difference in the described characteristic relative to that in a control, wildtype or unmodified potato plant;

"stress" or variants thereof, when used in relation to stresses experienced by potato plants and tubers, includes the effects of environment, fertility, moisture, temperature, handling, disease, atmosphere and aging that impact upon plant or tuber quality and which may be experienced by potato plants through all stages of their life cycle and by tubers at all stages of the growth and development cycle and during subsequent harvesting, transport, storage and processing;

"stress resistance" or variants thereof, shall mean reduced effects of temperature, aging, disease, atmosphere, physical handling, moisture, chemical residues, environment, pests and other stresses;

"suitable host" refers to a microorganism or cell that is compatible with a recombinant plasmid, DNA sequence or recombinant expression cassette and will permit the plasmid to replicate, to be incorporated into its genome, or to be expressed; and

"uninterrupted" refers to a DNA sequence (e.g. cDNA) containing an open reading frame that lacks intervening, untranslated sequences.

EXAMPLE 1

This example describes the reduction of GHTP and/or GLTP activity in tubers of potato plants by transforming potato plants with expression cassettes containing DNA sequences derived from the GLTP and GHTP gene sequences linked to the promoter in the antisense orientation.

A Isolation of Potato Tuber mRNA

Potato total RNA was purified at 4.degree. C. using autoclaved reagents from 1 g of tuber tissue ground to a fine powder under liquid nitrogen with a mortar and pestle. The powder was transferred to a 30 ml corex tube and 3 volumes were added of 100 mM Tris-Cl, pH 8.0, 100 mM NaCl, and 10 mM EDTA (10.times. TNE) containing 0.2% (w/v) SDS and 0.5% (v/v) 2-mercaptoethanol. An equal volume of phenol-chloroform (1:1) was added and the sample gently vortexed before centrifugation at 4.degree. C. in a SS34 rotor at 8,000 rpm for 5 min. The organic phase was reextracted with 0.5 volume of 10.times. TNE containing 0.2% (w/v)SDS and 0.5% (v/v) 2-mercaptoethanol and the combined aqueous phases were extracted with chloroform. Nucleic acids were precipitated from the aqueous phase with sodium acetate and absolute ethanol, pelleted by centrifugation, and resuspended in 3 ml of 1.times. TNE. An equal volume of 5 M LiCl was added and the sample stored at -20.degree. C. for at 4 h before centrifuging at 8,000 rpm in a SS34 rotor at 4.degree. C. for 10 min. The RNA pellet was washed with 70% ethanol, dried, and resuspended in DEPC-treated water.

Poly (A.sup.+) RNA was isolated using oligo (dT) cellulose (Boehringer Mannheim) column chromatography. Poly (A.sup.+) RNA was isolated from total RNA resuspended in RNAse free water. Columns were prepared using an autoclaved Bio-Rad Poly-Prep 10 ml column to which was added 50 mg of oligo (dT) cellulose suspended in 1 ml of loading buffer B which contains 20 mM Tris-Cl, pH 7.4, 0.1 M NaCl, 1 mM EDTA, and 0.1% (w/v) SDS. The column was washed with 3 volumes of 0.1 M NaOH with 5 mM EDTA and then DEPC-treated water until the pH of effluent was less than 8, as determined with pH paper. The column was then washed with 5 volumes of loading buffer A containing 40 mM Tris-Cl, pH 7.4, 1 M NaCl, 1 mM EDTA, and 0. 1 % (w/v) SDS.

RNA samples were heated to 65.degree. C. for 5 min at which time 400 .mu.l of loading buffer A, prewarmed to 65.degree. C., was added. The sample was mixed and allowed to cool at room temperature for 2 min before application to the column. Eluate was collected, heated to 65.degree. C. for 5 min, cooled to room temperature for 2 min, and reapplied to the column. This was followed by a 5 volume washing with loading buffer A followed by a 4 volume wash with loading buffer B. Poly (A.sup.+) RNA was eluted with 3 volumes of 10 mM Tris-Cl, pH 7.4, 1 mM EDTA, and 0.05% (w/v) SDS. Fractions were collected and those containing RNA were identified in an ethidium bromide plate assay, a petri dish with 1 % agarose made with TAE containing EtBr. RNA was precipitated, resuspended in 10 .mu.l, and a 1 .mu.l aliquot quantitated with a spectrophotometer.

B Isolation of GLTP and GHTP DNA Sequences

The nucleotide sequences utilized in the development of the antisense construct were randomly selected from the 5' sequence of GLTP (SEQ ID NO: 1) and GHTP (SEQ ID NO: 3). DNA sequences used to develop the antisense constructs were obtained using reverse transcription-polymerase chain reaction. GLTP (SPL1 and SPL2)- and GHTP (SPH1 and SPH2)-specific primers were designed according to the published sequences (Brisson et al. 1990, Fukui et al. 1991) with minor modifications to facilitate restriction with enzymes:

SPL1 Primer: 5'ATTCGAAAAGCTCGAGATTTGCATAGA3' (SEQ ID NO: 7) (additional CG creates Xho I site);

SPL2 Primer: 5'GTGTGCTCTCGAGCATTGAAAGC3' (SEQ ID NO: 8) (changed C to G to create Xho I site);

SPH1 Primer: 5'GTTTATTTTCCATCGATGGAAGGTGGTG3' (SEQ ID NO: 9) (added CGAT to create Cla I site);

SPH2 Primer: 5'ATAATATCCTGAATCGATGCACTGC3' (SEQ ID NO: 10) (changed G to T to create Cla I site).

Reverse transcription was performed in a volume of 15 .mu.l containing 1.times.PCR buffer (10 mM Tris-Cl pH 8.2, 50 mM KCl, 0.001% gelatin, 1.5 mM MgCl.sub.2), 670 .mu.M of each dNTP, 6 .mu.g of total potato tuber cv. Russet Burbank RNA, 1 mM each primer (SPH1 and SPL2, or SPH1 and SPH2) and 200 U of Maloney murine leukemia virus reverse transcriptase (BRL). The reaction was set at 37.degree. C. for 30 minutes, then heat-killed at 94.degree. C. for 5 minutes and snap cooled on ice. To the reverse transcription reaction was added 2.5 U Taq DNA polymerase (BRL) in 35 .mu.l of 1.times.PCR buffer. DNA amplification was done in a Perkin Elmer 480 programmed for 30 cycles with a 1 min 94.degree. C. denaturation step, a 1 min 56.degree. C. (SPL1 and SPL2) or 58.degree. C. (SPH1 and SPH2) annealing step, and a 2 min 72.degree. C. extension step. PCR was completed with a final 10 min extension at 72.degree. C.

C Construction of SP Vectors for Phosphorylase Inhibition

To express the antisense constructs in plant cells, it was necessary to fuse the genes to the proper plant regulatory regions. This was accomplished by cloning the antisense DNA into a plasmid vector that contained the needed sequences.

Amplified DNA was blunt ended and cloned into a pUC 19 vector at the SmaI site. The recombinant plasmid was transformed into sub-cloning efficiency E. coli DH5.alpha. cells (BRL). The transformed cells were plated on LB (15 g/l Bactotyptone, 5 g/l yeast extract, 10 g/l NaCl, pH 7.3, and solidified with 1.5% agar) plates that contained ampicillin at 100 ug/ml Selection of bacteria containing plasmids with inserted plant phosphorylase sequence was accomplished using color selection. The polylinker and T3 and T7 RNA polymerase promoter sequences are present in the N-terminal portion of the lacZ gene fragment. pUC19 plasmids without inserts in the polylinker grow as blue colonies in appropriate bacterial strains such as DH5.alpha.. Color selection was made by spreading 100 .mu.l of 2% X-gal (prepared in dimethyl formamide) on LB plates containing 50 .mu.g/ml ampicillin 30 minutes prior to plating the transformants. Colonies containing plasmids without inserts will be blue after incubation for 12 to 18 hours at 37.degree. C. and colonies with plasmids containing inserts will remain white. An isolated plasmid was sequenced to confirm the sequence of the phosphorylase inserts. Sequences were determined using the ABI Prism Dye Terminator Cycle Sequencing Core Kit (Applied Biosystems, Foster City, Calif.), M13 universal and reverse primers, and an ABI automated DNA sequencer. The engineered plasmid was purified by the rapid alkaline extraction procedure from a 5 ml overnight culture (Birnboim and Doly, 1979). Orientation of the SPL and SPH fragments in pUC19 was determined by restriction enzyme digestion. The recombinant pUC19 vectors and the binary vector pBI121 (Clonetech) were restricted, run on a agarose gel and the fragments purified by gel separation as described by Thuring et al (1975).

Ligation fused the antisense sequence to the binary vector pBI121. The ligation contained pBI121 vector that had been digested with BamHI and SacI, along with the SPL or SPH phosphorylase DNA product, that had been cut from the pUC19 subclone with BamHI and SacI. Ligated DNA was transformed into SCE E. coli DH5.alpha. cells, and the transformed cells were plated on LB plates containing ampicillin. The nucleotide sequences of the antisense DNA SPL and SPH are nucleotides 338 to 993 of SEQ ID NO: 1 and nucleotides 147 to 799 of SEQ ID NO: 3, respectively. Selection of pBI121 with phosphorlylase inserts was done with CAMV and NOS specific primers.

Samples 1 and 2 representing the tuber L-type and tuber H-type phosphorylase DNA fragments were picked from a plate after overnight growth. These samples were inoculated into 5 ml of LB media and grown overnight at 37.degree. C. Plasmids were isolated by the rapid alkaline extraction procedure, and the DNA was electroporated into Agrobacterium tumefaciens.

Constructs were engineered into the pBI121 vector that contains the CAMV 35S promoter (Kay et al. 1987) and the NOS 3' terminator (Bevan et al. 1983) sequence. The pBI121 plasmid is made up of the following well characterized segments of DNA. A 0.93 kb fragment isolated from transposon Tn7 which encodes bacterial spectinomycin/streptomycin (Spc/Str) resistance and is a determinant for selection in E. coli and Agrobacterium tumefaciens (Fling et al., 1985). This is joined to a chimeric kanamycin resistance gene engineered for plant expression to allow selection of the transformed tissue. The chimeric gene consists of the 0.35 kb cauliflower mosaic virus 35S promoter (P-35S) (Odell et al., 1985), the 0.83 kb neomycin phosphotransferase type II gene (NPTII), and the 026 kb 3' non-translated region of the nopaline synthase gene (NOS 3') (Fraley et al., 1983). The next segment is a 0.75 kb origin of replication from the RK2 plasmid (ori-V) (Stalker et al., 1981). It is joined to a 3.1 kb SalI to PvuI segment of pBR322 which provides the origin of replication for maintenance in E. coli (ori-322) and the bom site for the conjugational transfer: in the Agrobacterium tumefaciens cells. Next is a 0.36 kb PvuI fragment from the pTiT37 plasmid which contains the nopaline-type T-DNA right border region (Fraley et al., 1985). The antisense sequence was engineered for expression in the tuber by placing the gene under the control of a constitutive tissue non-specific promoter.

D Plant Transformation/Regeneration

The SPL and SPH vectors were transformed into the Desiree potato cultivar according to de Block (1988). To transform "Desiree" potatoes, sterile shoot cultures of "Desiree" were maintained in test tubes containing 8 ml of S 1 (Murashige and Skoog (MS) medium supplemented with 2% sucrose and 0.5 g/l MES pH 5.7, solidified with 6 g/l Phytagar). When plantlets reached approximately 5 cm in length, leaf pieces were excised with a single cut along the base and inoculated with a 1:10 dilution of an overnight culture of Agrobacterium tumefaciens. The stem explants were co-cultured for 2 days at 20.degree. C. on S1 medium (De Block 1988). Following co-culture, the explants were transferred to S4 medium (MS medium without sucrose, supplemented with 0.5 g/l MES pH 5.7, 200 mg/l glutamine, 0.5 g/l PVP, 20 g/l mannitol, 20 g/l glucose, 40 mg/l adenine, 1 mg/l trans zeatin, 0.1 mg/l NAA, 1 g/l carbenicillin, 50 mg/l kanamycin, solidified with 6 g/l phytagar) for 1 week and then 2 weeks to induce callus formation.

After 3 weeks, the explants were transferred to S6 medium (S4 without NAA and with half the concentration (500 mg/1) of carbenicillin). After another two weeks, the explants were transferred to S8 medium (S6 with only 250 mg/l carbenicillin and 0.01 mg/l gibberellic acid, GA3) to promote shoot formation. Shoots began to develop approximately 2 weeks after transfer to S8 shoot induction medium. These shoots were excised and transferred to vials of S1 medium for rooting. After about 6 weeks of multiplication on the rooting medium, the plants were transferred to soil and are gradually hardened off.

Desiree plants regenerated in culture were transplanted in 1 gallon pots and were grown to maturity under greenhouse conditions. Tubers were harvested and allowed to suberize at room temperature for two days. All tubers greater than 2 cm in length were collected and stored at 4.degree. C. under high humidity.

E Field Trials

Untransformed controls, plants expressing the SPL construct, and plants expressing the SPH construct were propagated in field trials in a single replicate randomized design. All plants were grown side by side in the same field and exposed to similar pesticide, fertilizer, and irrigation regimes. Tubers were harvested and stored at 10.degree. C. for 2 weeks before randomly selecting a fraction of the tubers from each line to be placed in storage at 4.degree. C.

F Sugar Analysis

Tubers were stored at 4.degree. C. and were not allowed to recondition at room temperature prior to sugar analysis. An intact longitudinal slice (1 cm thick, width variable and equal to the outside dimensions of the tuber) was cut from the central portion of each tuber, thus representing all of the tuber's tissues. At each harvest, the central slices from four tubers per clone (3 replicates) were collectively diced into 1-cm cubes and 15 g was randomly selected from the pooled tissue for analysis. Glucan phosphorylase (see below) and sugars were extracted with 15 mL of Tris buffer (50 mM, pH 7.0) containing 2 mM sodium bisulfite, 2 mM EDTA. 0.5 mM PMSF and 10% (w/w) glycerol with a polytron homogenizer at 4.degree. C. The extracts were centrifuged at 4.degree. C. (30,000 g, 30 min) and reducing sugars (glucose and fructose) were measured on a 10-fold dilution of the supernatant using a Spectra Physics high performance liquid chromatograph interfaced to a refractive index detector. The separation was performed at 80.degree. C. on a 30.times.0.78 cm Aminex HPX 87C column (Biorad) using 0.6 ml/min water as the mobile phase. Calibration of the instrument was via authentic standards of d-glucose and d-fructose.

G Analysis of .alpha.-Glucan Phosphorylase Activity

Tubers stored at 4.degree. C. were not allowed to warm prior to extraction and analysis of a glucan phosphorylase activity and isozymes. The in vitro activity of glucan phosphorylase in the phosphorolytic direction was assayed as described by Steup (1990). Briefly, samples of extracts obtained for sugar analysis (see above) were added to a reaction medium which coupled starch phosphorolysis to the reduction of NADP through the sequential actions of phosphoglucomutase and glucose-6-phosphate dehydrogenase. The rate of reduction of NADP during the reaction is stoichiometric with the rate of production of glucose-1-phosphate from the starch substrate. Reduction of NADP was followed at 340 nm in a Varian Cary double-beam spectrophotometer. Protein levels in extracts were determined according to Bradford (1976).

Glucan phosphorylase activity gels were run essentially according to Steup (1990). Proteins were separated on native polyacrylarnide gels (8.5 %) containing 1.5 % glycogen. Following electrophoresis at 80 V for 15 h (4.degree. C.), the gels were incubated (1-2 h) at 37.degree. C. in 0.1 M citrate-NaOH buffer (pH 6.0) containing 20 mM glucose-1-P and 0.05% (w/v) hydrolyzed potato starch. Gels were then rinsed and stained with an iodine solution. For Western blot analysis, proteins were electrophoresed on glycogen-containing polyacrylamide gels as described above. The proteins were electroblotted to nitrocellulose and blots were probed with polyclonal antibodies raised against GHTP and GLTP. Immunoblots were developed with alkaline phosphatase conjugated anti-rabbit secondary antibodies (Sigma).

H Chip Color Determination

Five transgenic potato lines expressing the GLTP antisense sequence, two transgenic lines expressing the GHTP antisense sequence, non-transgenic Desiree control lines, and two control lines transformed with the pBI121 vector T-DNA, were grown under field conditions in Alberta, Canada. Tubers were harvested and stored at 10.degree. C. and 4.degree. C. Chip color was determined for all potato lines by taking center cuts from representative samples from each line and frying at 205.degree. F. in soybean oil for approximately 3 minutes until bubbling stops.

Results

All tubers were harvested from plants of the same cultivar (Desiree), the same age, and grown side by side under identical growth conditions. Northern analysis of tubers showed a considerable reduction of endogenous GLTP transcript in transgenic plants expressing the homologous antisense transcript (FIG. 7). Glucan phosphorylase assays showed that activities (.mu.mol NADPH mg.sup.-1 protein h.sup.-1) were reduced (Table 1) at harvest and for at least six months following harvest in transgenic plants expressing the GLTP antisense DNA. The results tabulated in Table 1 show that .alpha. glucan phosphorylase activity in tubers stored at 4.degree. C. for 189 days was reduced from approximately 16% to 70% in various transformed potato varieties relative to the wildtype control strain. Activity gels and western blot analysis showed specific reduced expression of homologous enzymes and lower reduction of expression for heterologous enzymes (FIGS. 10 and 11). This specificity for homologous products may result from differences between the phosphorylases (FIGS. 6A and 6B).

Analysis of tubers at harvest (0 days) shows that those expressing the antisense GLTP transcript have up to 5-fold less reducing sugars than control tubers (Table 2). Furthermore, after 91 days storage at 4.degree. C., transformed tubers contained 28-39% lower reducing sugar concentrations than the wildtype control strain. Concentrations of glucose and fructose were reduced significantly in tubers expressing the antisense GLTP transcript (Tables 3 and 4). These results suggest that reduced GLTP activity slows the catabolism of starch into reducing, sugars in tubers, while in the control tubers the sugars continue to accumulate. The correlation between total phosphorylase activity and the concentration of reducing sugars is not direct, suggesting that certain isozymes of phosphorylase may play a more important role in the catabolism of starch, that specific levels of reduced expression of particular phosphorylase isozymes may be more optimum than others, and/or that there may be unidentified interactions involved in the lower reducing sugar levels.

Transgenic potato plants expressing the antisense GLTP or GHTP transcript have been grown under field conditions and their tubers stored at 4.degree. C. Chip color, which correlated with sugar content, was determined prior to cold storage and after 86 and 124 days of cold storage. The chip color of tubers from all transgenic plants expressing the antisense GLTP transcript was significantly improved (lighter) relative to that of control tubers (darker) stored under identical conditions (Table 5 and FIG. 9). Chip scores of tubers from "Desiree" potato plants expressing the GLTP transcript were improved by at least 4.3 points and 8.9 points as determined with an Agtron model E-15-FP Direct Reading Abridged Spectrophotometer (Agtron Inc. 1095 Spice Island Drive #100, Sparks Nevada 89431) following storage at 10.degree. C. and 4.degree. C., respectively, for 86 days. Chip scores of GLTP transformants measured after 124 days of storage at 4.degree. C. were improved by 44% to 89% relative to wildtype (Table 5).

The Desiree cultivar is not a commercially desirable potato for chipping due to its high natural sugar content and propensity to sweeten rapidly in cold storage. Nevertheless, significant improvements in fried chip color were noted with the transformed "Desiree" potatoes. It is expected that superior color lightening would be achieved if the methods of the invention were applied to commercial processing potato varieties.

Analysis of tubers stored at 10.degree. C. and 4.degree. C. shows that those expressing the antisense GHTP transcript sometimes provided chips that fried lighter than control tubers, indicating a lower buildup of reducing sugars (Table 5). Results showing heterologous and homologous reduction in phosphorylase activity (FIGS. 10 and 11) indicate that the improvement may be a result of reducing one or both tuber phosphorylases. However, these results suggest that the L-type phosphorylase plays a more important role in the catabolism of starch into reducing sugars.

Further, the results show that the difference in reducing sugar levels (Table 2) and chip scores (Table 5) between tubers wildtype plants and those expressing tuber phosphorylase antisense RNA, are sustained during long-term storage. As shown in Table 5, the chip scores are approximately the same at 86 days and 124 days. No further increases in reducing sugar concentrations were evident after 49 and 91 days storage at 4.degree. C. (Table 2). This equilibrium in sugar concentration was probably associated with the kinetics of the tuber phosphorylases. The capability of maintaining lower sugar levels has the potential of extending the period of storage by at least several months. Presently, processing potatoes are usually stored for a maximum of three to six months at 10.degree. C. to 12.degree. C. before the sugar accumulation reaches levels that reduce quality. Fresh product must be imported until the present season potatoes become available. Extending the storage period of potatoes by many months may reduce import costs.

Table 6 provides a summary of the percentage improvement in various improved tuber cold-storage characteristics of tubers of potato plants transformed with antisense DNA derived from the GLTP gene sequence (ATL3-ATL9), and from the GHTP gene sequence (ATH1 and ATH2) relative to untransformed control plants. It is apparent from the results summarized in Table 6 that substantial improvements in tuber cold-storage characteristics may be consistently obtained through the methods of the present invention. Particularly noteworthy are the percentage chip score improvements over wildtype observed after storage at 4.degree. C. for approximately four months (124 days). Relative chip score improvements of up to 89% relative to wildtype were observed. Improved chip scores reflect the commercial utility of the invention. That is, by reducing cold-induced sweetening, tubers can be stored at cooler. temperatures, without causing unacceptable darkening of fried potato products.

The reduction in sugar accumulation of transformed potato lines relative to wildtype, both at harvest and after 91 day storage, also demonstrates significant advantages of the invention. Reduced sugar accumulation relates to the observed chip score improvements, and also reflects improved specific gravity of tubers, another important commercial measure of tuber quality.

Even at harvest, substantial improvements in chip score and reduced sugar accumulation were noted for transformed lines relative to wildtype. Thus, the benefits of the invention are not limited to improvements that arise only after extended periods of cold storage, but that are present at the time of harvest. In this sense, the invention is not limited only to improvements in cold-storage characteristics but encompasses improvements in tuber quality characteristics such as chip score or sugar accumulation which are present at the time of harvest, resulting in earlier maturity.

Turning to specific improvements summarized in Table 6, it can be seen that GLTP-type transformants (ATL3-ATL9) exhibited up to a 66%, 70% and 69% reduction in .alpha. glucan phosphorylase activity relative to wildtype, at harvest, and after storage for 91 and 189 days, respectively. Most also exhibited improvements in excess of 10% and 30% relative to wildtype at harvest and after storage for 91 and 189 days. After storage for 91 and 189 days, the GHTP-type transformants (ATH1 and ATH2) exhibited, respectively, up to 28% and 39% relative improvement over wildtype and generally showed at least 10% improvement.

The GLTP-type transformants exhibited up to 80% and 39% reduction of sugar accumulation relative to wildtype at harvest and at 91 days, respectively. At harvest, all GLTP-type transformants exhibited at least 10% and at least 30% relative improvement. At 91 days, all GLTP-type transformants exhibited at least 10% and most exhibited at least 30% relative improvement.

The GLTP-type transformants exhibited up to 46%, 89% and 89% chip score improvement relative to wildtype at harvest, and after storage for 86 days and 124 days, respectively. Almost all exhibited at least 10% and 30% relative improvement at harvest, and after storage for 86 and 124 days. At least one of the GHTP-type transformants exhibited at least 5% and at least 10% improvement relative to wildtype at harvest, and after storage for 86 and 124 days. After 124 days storage, at least one of the GHTP-type transformants exhibited up to 25% relative improvement in chip score.

The results clearly demonstrate that substantial improvements in tuber cold-storage characteristics may be readily obtained through the methods of the invention. Results will vary due to, among other things, the location within the plant genome where the recombinant antisense or sense DNA is inserted, and the number of insertion events that occur. It is important to note that despite the variability in the results amongst the various transformed lines, there was little variation in the results amongst the samples within a single transformed potato line (see footnotes to Tables 1 to 5). Results are presented in Table 6 for all potato plant lines which were successfully transformed with the GHTP or GLTP antisense DNA. Therefore, all transformants show at least some improvement in one or more cold-storage characteristics such as increased chip score (lighter color on cooking) and reduced sugar accumulation, and most show very substantial improvements. Given the large proportion of positive transformants observed in the examples herein, it is expected that, using the cold-storage characteristic testing, procedures described in the examples, potato plants transformed through the methods of the invention can be readily screened to identify transformed lines exhibiting significantly improved cold-storage characteristics. By applying the techniques disclosed herein to commercially important potato varieties, it will be possible to readily create and select transformants having significantly improved cold-storage characteristics. Those transformants showing the greatest relative improvements over wildtype controls can be used in the development of new commnercial potato varieties.

                TABLE 1                                                     
     ______________________________________                                    
     Effects of an antisense transcript on glucan phosphorylase activity       
      measured in enzyme extracts from field grown "Desiree" tubers.           
                Glucan Phosphorylase Activity                                  
                 Storage Period at 4C (days)                                   
     Clone      0        49     91     140  189                                
     ______________________________________                                    
     .mu.mol NADPH mg.sup.-1 protein b.sup.-1                                  
         Wt.sup.a   10.50    11.83                                             
                                  9.94   11.90                                 
                                              13.04                            
       ATL3 4.90 4.86 4.49 4.73 4.88                                           
       ATL4 11.45 7.17 8.09 11.32 10.99                                        
       ATL5 3.58 3.56 2.97 4.59 4.79                                           
       ATL9 3.59 3.88 3.84 4.72 3.98                                           
       LSD.sub.0.05.sup.b 1.97 2.94 1.59 2.34 2.58                             
       LSD.sub.0.01 2.87 4.28 2.31 3.41 3.75                                   
       Clone.sup.c  0.01.sup.d                                                 
       WT vs. ATL's  0.01                                                      
       Days  NS                                                                
       Clone .times. Days  0.05                                                
       Wt  11.49 8.90 12.66 13.66                                              
       ATH-1  10.40 9.69 10.79 10.10                                           
       ATH-2  6.46 6.40 6.56 8.38                                              
       LSD.sub.0.05.sup.b  2.02 0.41 3.00 NS                                   
       LSD.sub.0.01  4.78 0.95 NS NS                                           
       Clone.sup.c  0.01                                                       
       WT vs. ATH's  0.01                                                      
       Days  0.05                                                              
       Clone .times. Days  NS                                                  
     ______________________________________                                    
      .sup.a WT, wild type untransformed tubers.                               
      .sup.b LSD, least significant difference at 0.05 or 0.01 level for each  
      storage period.                                                          
      .sup.c Sources of variation in factorial analysis.                       
      .sup.d Significance levels for indicated sources of variation.           

                TABLE 2                                                     
     ______________________________________                                    
     Effects of an antisense GLTP transcript on low temperature induced        
      sweetening of field grown "Desiree" tubers.                              
                 Reducing Sugars (glucose + fructose)                          
                  Storage Period at 4C (days)                                  
     Clone       0            49     91                                        
     ______________________________________                                    
     mg g.sup.-1 fresh weight                                                  
          Wt.sup.a   5.63         31.8 28.0                                    
       ATL3 1.88 17.3 17.3                                                     
       ATL4 1.11 14.3 20.1                                                     
       ATL5 1.51 18.3 17.0                                                     
       ATL9 1.36 17.3 18.5                                                     
       WT vs. ATL's.sup.b 0.01 0.01 0.05                                       
       Clone.sup.c  0.01.sup.d                                                 
       Days  0.01                                                              
       Clone .times. Days  NS                                                  
     ______________________________________                                    
      .sup.a WT, wild type untransformed tubers.                               
      .sup.b Orthogonal comparisons for ANOVA's at each storage period,        
      .sup.c sources of variation in factorial analysis.                       
      .sup.d Significance levels for indicated sources of variation.           

                TABLE 3                                                     
     ______________________________________                                    
     Effects of antisense GLTP transcript on low temperature induced fructose  
      accumulation of field grown "Desiree" tubers.                            
                 Fructose                                                      
                  Storage Period at 4C (days)                                  
     Clone       0            49     91                                        
     ______________________________________                                    
     mg g.sup.-1 fresh weight                                                  
          Wt.sup.a   3.53         15.10                                        
                                       12.20                                   
       ATL3 1.21 8.40 8.79                                                     
       ATL4 0.79 7.22 8.56                                                     
       ATL5 0.61 10.00 8.09                                                    
       ATL9 0.54 8.38 8.72                                                     
       WT vs. ATL's.sup.b 0.01 0.01 NS                                         
       Clone.sup.c  0.01.sup.d                                                 
       Days  0.01                                                              
       Clone .times. Days  NS                                                  
     ______________________________________                                    
      .sup.a WT, wild type untransformed tubers.                               
      .sup.b Orthogonal comparisons for ANOVA's at each storage period,        
      .sup.c Sources of variation in factorial analysis.                       
      .sup.d Significance levels for indicated sources of variation.           

                TABLE 4                                                     
     ______________________________________                                    
     Effects of antisense GLTP transcript on low temperature induced glucose   
      accumulation of field grown "Desiree" tubers.                            
                 Glucose                                                       
                  Storage Period at 4C (days)                                  
     Clone       0            49     91                                        
     ______________________________________                                    
     mg g.sup.-1 fresh weight                                                  
          Wt.sup.a   2.10         16.60                                        
                                       15.90                                   
       ATL3 0.68 8.94 8.49                                                     
       ATL4 0.32 7.07 11.06                                                    
       ATL5 1.05 8.33 8.91                                                     
       ATL9 0.83 8.87 9.78                                                     
       WT vs. ATL's.sup.b 0.01 0.01 0.05                                       
       Clone.sup.c  0.01.sup.d                                                 
       Days  0.01                                                              
       Clone .times. Days  NS                                                  
     ______________________________________                                    
      .sup.a WT, wild type untransformed tubers.                               
      .sup.b Orthogonal comparisons for ANOVA's at each storage period,        
      .sup.c sources of variation in factorial analysis.                       
      .sup.d Significance levels for indicated sources of variation.           

                TABLE 5                                                     
     ______________________________________                                    
     Average chip color of field grown "Desiree" tubers. The chip color rating 
      was assigned using an Agtron meter similar to that used by industry to   
      measure color of fried potatoes. In this index, the higher the number    
     the                                                                       
       lighter the chip product but color does not represent a linear relations
     hip                                                                       
      to the index.                                                            
              Storage Temperature, Period, and Agtron Reading.sup.a            
                          86 days  86 days                                     
                                         124 days                              
       Harvest 10C 4C 4C                                                       
     ______________________________________                                    
     Wt.sup.b 26      25.3       15.4  17.1                                    
       ATL3.sup.c 25 37.4 26.7 30.8                                            
       ATL4 35 43.7 29.1 32.3                                                  
       ATL5 36 29.6 24.7 24.6                                                  
       ATL9 38 38.7 24.3 26.6                                                  
       ATH1.sup.d 26 49.7 17.5 21.4                                            
       ATH2 29 31.2 15.6 15.9                                                  
       GMP1.sup.e 31  15.7 15.7                                                
       GMP2 35  16.7 16.6                                                      
     ______________________________________                                    
      .sup.a Agtron Inc. 1095 Spice Island Drive #100, Sparks Nevada 89431.    
      Agtron model E15-FP (Direct Reading Abridged Spectrophotometer). Measures
      ratio of reflectance in two spectral modes, near infrared and green.     
      Results represent the measurement of 6 to 8 chips from 3 randomly selecte
      tubers approximately 3 to 4 cm in diameter.                              
      .sup.b WT, negative control, wild type untransformed tubers.             
      .sup.c ATL, tubers transformed with the tuber Ltype.varies. glucan       
      phosphorylase.                                                           
      .sup.d ATH, tuber transformed with the tuber Htype.varies. glucan        
      phosphorylase.                                                           
      .sup.e GMP, negative control, tubers transformed with pBI121 TDNA.       

                TABLE 6                                                     
     ______________________________________                                    
     Summary of Results                                                        
                         % Reduction of                                        
       % Reduction of a .alpha.  Sugar % Chip Score                            
       glucan phosphorylase Accumulation Improvement                           
       activity relative to relative to relative to                            
       wildtype wildtype wildtype                                              
           at      91     189  at    91   at    86   124                       
       Sample harvest days days harvest days harvest days days                 
     ______________________________________                                    
     ATL3  53      55     63   67    38   -4    73   80                        
       ATL4 -9 19 16 80 28 35 89 89                                            
       ATL5 66 70 63 73 39 38 60 44                                            
       ATL9 66 61 69 76 34 46 58 56                                            
       ATH1 n/a -9 26 n/a n/a 0 14 25                                          
       ATH2 n/a 28 39 n/a n/a 12 1 -7                                          
     ______________________________________                                    

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All publications mentioned in this specification are indicative of the level of skill in the art to which this invention pertains. All publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be obvious that certain changes and modifications may be practised within the scope of the appended claims.

  __________________________________________________________________________
     #             SEQUENCE LISTING                                            
        - -  - - (1) GENERAL INFORMATION:                                      
        - -    (iii) NUMBER OF SEQUENCES: 10                                   
        - -  - - (2) INFORMATION FOR SEQ ID NO:1:                              
        - -      (i) SEQUENCE CHARACTERISTICS:                                 
                 (A) LENGTH: 3101 base - #pairs                                
                 (B) TYPE: nucleic acid                                        
                 (C) STRANDEDNESS: double                                      
                 (D) TOPOLOGY: linear                                          
        - -     (ii) MOLECULE TYPE: DNA (genomic)                              
        - -    (iii) HYPOTHETICAL: NO                                          
        - -     (iv) ANTI-SENSE: NO                                            
        - -     (vi) ORIGINAL SOURCE:                                          
                 (A) ORGANISM: Solanum t - #uberosum                           
        - -     (ix) FEATURE:                                                  
                 (A) NAME/KEY: CDS                                             
                 (B) LOCATION: 44..2944                                        
                 (D) OTHER INFORMATION: - #/product= "potato alpha-glucan      
                     L-type tu - #ber phosphorylase"                           
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: mat.sub.-- - #peptide                            
                (B) LOCATION: 194..2941                                        
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: sig.sub.-- - #peptide                            
                (B) LOCATION: 44..193                                          
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:                         
       - - ATCACTCTCA TTCGAAAAGC TAGATTTGCA TAGAGAGCAC AAA ATG GC - #G ACT GCA 
           55                                                                  
                        - #                  - #            Met Ala Thr Al -   
     #a                                                                        
                         - #                  - #            -50               
        - - AAT GGA GCA CAC TTG TTC AAC CAT TAC AGC TC - #C AAT TCC AGA TTC    
     ATC      103                                                              
       Asn Gly Ala His Leu Phe Asn His Tyr Ser Se - #r Asn Ser Arg Phe Ile     
          -45              - #   -40              - #   -35                    
       - - CAT TTC ACT TCT AGA AAC ACA AGC TCC AAA TT - #G TTC CTT ACC AAA ACC 
          151                                                                  
      His Phe Thr Ser Arg Asn Thr Ser Ser Lys Le - #u Phe Leu Thr Lys Thr      
     30                 - - #25                 - - #20                 - -    
     #15                                                                       
        - - TCC CAT TTT CGG AGA CCC AAA CGC TGT TTC CA - #T GTC AAC AAT ACC    
     TTG      199                                                              
       Ser His Phe Arg Arg Pro Lys Arg Cys Phe Hi - #s Val Asn Asn Thr Leu     
                      -10  - #                -5  - #                 1        
       - - AGT GAG AAA ATT CAC CAT CCC ATT ACT GAA CA - #A GGT GGT GAG AGC GAC 
          247                                                                  
      Ser Glu Lys Ile His His Pro Ile Thr Glu Gl - #n Gly Gly Glu Ser Asp      
                5        - #          10        - #          15                
       - - CTG AGT TCT TTT GCT CCT GAT GCC GCA TCT AT - #T ACC TCA AGT ATC AAA 
          295                                                                  
      Leu Ser Ser Phe Ala Pro Asp Ala Ala Ser Il - #e Thr Ser Ser Ile Lys      
           20             - #     25             - #     30                    
       - - TAC CAT GCA GAA TTC ACA CCT GTA TTC TCT CC - #T GAA AGG TTT GAG CTC 
          343                                                                  
      Tyr His Ala Glu Phe Thr Pro Val Phe Ser Pr - #o Glu Arg Phe Glu Leu      
       35                 - # 40                 - # 45                 - # 50 
       - - CCT AAG GCA TTC TTT GCA ACA GCT CAA AGT GT - #T CGT GAT TCG CTC CTT 
          391                                                                  
      Pro Lys Ala Phe Phe Ala Thr Ala Gln Ser Va - #l Arg Asp Ser Leu Leu      
                       55 - #                 60 - #                 65        
       - - ATT AAT TGG AAT GCT ACG TAT GAT ATT TAT GA - #A AAG CTG AAC ATG AAG 
          439                                                                  
      Ile Asn Trp Asn Ala Thr Tyr Asp Ile Tyr Gl - #u Lys Leu Asn Met Lys      
                   70     - #             75     - #             80            
       - - CAA GCG TAC TAT CTA TCC ATG GAA TTT CTG CA - #G GGT AGA GCA TTG TTA 
          487                                                                  
      Gln Ala Tyr Tyr Leu Ser Met Glu Phe Leu Gl - #n Gly Arg Ala Leu Leu      
               85         - #         90         - #         95                
       - - AAT GCA ATT GGT AAT CTG GAG CTT ACT GGT GC - #A TTT GCG GAA GCT TTG 
          535                                                                  
      Asn Ala Ile Gly Asn Leu Glu Leu Thr Gly Al - #a Phe Ala Glu Ala Leu      
          100              - #   105              - #   110                    
       - - AAA AAC CTT GGC CAC AAT CTA GAA AAT GTG GC - #T TCT CAG GAA CCA GAT 
          583                                                                  
      Lys Asn Leu Gly His Asn Leu Glu Asn Val Al - #a Ser Gln Glu Pro Asp      
      115                 1 - #20                 1 - #25                 1 -  
     #30                                                                       
        - - GCT GCT CTT GGA AAT GGG GGT TTG GGA CGG CT - #T GCT TCC TGT TTT    
     CTG      631                                                              
       Ala Ala Leu Gly Asn Gly Gly Leu Gly Arg Le - #u Ala Ser Cys Phe Leu     
                      135  - #               140  - #               145        
       - - GAC TCT TTG GCA ACA CTA AAC TAC CCA GCA TG - #G GGC TAT GGA CTT AGG 
          679                                                                  
      Asp Ser Leu Ala Thr Leu Asn Tyr Pro Ala Tr - #p Gly Tyr Gly Leu Arg      
                  150      - #           155      - #           160            
       - - TAC AAG TAT GGT TTA TTT AAG CAA CGG ATT AC - #A AAA GAT GGT CAG GAG 
          727                                                                  
      Tyr Lys Tyr Gly Leu Phe Lys Gln Arg Ile Th - #r Lys Asp Gly Gln Glu      
              165          - #       170          - #       175                
       - - GAG GTG GCT GAA GAT TGG CTT GAA ATT GGC AG - #T CCA TGG GAA GTT GTG 
          775                                                                  
      Glu Val Ala Glu Asp Trp Leu Glu Ile Gly Se - #r Pro Trp Glu Val Val      
          180              - #   185              - #   190                    
       - - AGG AAT GAT GTT TCA TAT CCT ATC AAA TTC TA - #T GGA AAA GTC TCT ACA 
          823                                                                  
      Arg Asn Asp Val Ser Tyr Pro Ile Lys Phe Ty - #r Gly Lys Val Ser Thr      
      195                 2 - #00                 2 - #05                 2 -  
     #10                                                                       
        - - GGA TCA GAT GGA AAG AGG TAT TGG ATT GGT GG - #A GAG GAT ATA AAG    
     GCA      871                                                              
       Gly Ser Asp Gly Lys Arg Tyr Trp Ile Gly Gl - #y Glu Asp Ile Lys Ala     
                      215  - #               220  - #               225        
       - - GTT GCG TAT GAT GTT CCC ATA CCA GGG TAT AA - #G ACC AGA ACC ACA ATC 
          919                                                                  
      Val Ala Tyr Asp Val Pro Ile Pro Gly Tyr Ly - #s Thr Arg Thr Thr Ile      
                  230      - #           235      - #           240            
       - - AGC CTT CGA CTG TGG TCT ACA CAG GTT CCA TC - #A GCG GAT TTT GAT TTA 
          967                                                                  
      Ser Leu Arg Leu Trp Ser Thr Gln Val Pro Se - #r Ala Asp Phe Asp Leu      
              245          - #       250          - #       255                
       - - TCT GCT TTC AAT GCT GGA GAG CAC ACC AAA GC - #A TGT GAA GCC CAA GCA 
         1015                                                                  
      Ser Ala Phe Asn Ala Gly Glu His Thr Lys Al - #a Cys Glu Ala Gln Ala      
          260              - #   265              - #   270                    
       - - AAC GCT GAG AAG ATA TGT TAC ATA CTC TAC CC - #T GGG GAT GAA TCA GAG 
         1063                                                                  
      Asn Ala Glu Lys Ile Cys Tyr Ile Leu Tyr Pr - #o Gly Asp Glu Ser Glu      
      275                 2 - #80                 2 - #85                 2 -  
     #90                                                                       
        - - GAG GGA AAG ATC CTT CGG TTG AAG CAA CAA TA - #T ACC TTA TGC TCG    
     GCT     1111                                                              
       Glu Gly Lys Ile Leu Arg Leu Lys Gln Gln Ty - #r Thr Leu Cys Ser Ala     
                      295  - #               300  - #               305        
       - - TCT CTC CAA GAT ATT ATT TCT CGA TTT GAG AG - #G AGA TCA GGT GAT CGT 
         1159                                                                  
      Ser Leu Gln Asp Ile Ile Ser Arg Phe Glu Ar - #g Arg Ser Gly Asp Arg      
                  310      - #           315      - #           320            
       - - ATT AAG TGG GAA GAG TTT CCT GAA AAA GTT GC - #T GTG CAG ATG AAT GAC 
         1207                                                                  
      Ile Lys Trp Glu Glu Phe Pro Glu Lys Val Al - #a Val Gln Met Asn Asp      
              325          - #       330          - #       335                
       - - ACT CAC CCT ACA CTT TGT ATC CCT GAG CTG AT - #G AGA ATA TTG ATA GAT 
         1255                                                                  
      Thr His Pro Thr Leu Cys Ile Pro Glu Leu Me - #t Arg Ile Leu Ile Asp      
          340              - #   345              - #   350                    
       - - CTG AAG GGC TTG AAT TGG AAT GAA GCT TGG AA - #T ATT ACT CAA AGA ACT 
         1303                                                                  
      Leu Lys Gly Leu Asn Trp Asn Glu Ala Trp As - #n Ile Thr Gln Arg Thr      
      355                 3 - #60                 3 - #65                 3 -  
     #70                                                                       
        - - GTG GCC TAC ACA AAC CAT ACT GTT TTG CCT GA - #G GCA CTG GAG AAA    
     TGG     1351                                                              
       Val Ala Tyr Thr Asn His Thr Val Leu Pro Gl - #u Ala Leu Glu Lys Trp     
                      375  - #               380  - #               385        
       - - AGT TAT GAA TTG ATG CAG AAA CTC CTT CCC AG - #A CAT GTC GAA ATC ATT 
         1399                                                                  
      Ser Tyr Glu Leu Met Gln Lys Leu Leu Pro Ar - #g His Val Glu Ile Ile      
                  390      - #           395      - #           400            
       - - GAG GCG ATT GAC GAG GAG CTG GTA CAT GAA AT - #T GTA TTA AAA TAT GGT 
         1447                                                                  
      Glu Ala Ile Asp Glu Glu Leu Val His Glu Il - #e Val Leu Lys Tyr Gly      
              405          - #       410          - #       415                
       - - TCA ATG GAT CTG AAC AAA TTG GAG GAA AAG TT - #G ACT ACA ATG AGA ATC 
         1495                                                                  
      Ser Met Asp Leu Asn Lys Leu Glu Glu Lys Le - #u Thr Thr Met Arg Ile      
          420              - #   425              - #   430                    
       - - TTA GAA AAT TTT GAT CTT CCC AGT TCT GTT GC - #T GAA TTA TTT ATT AAG 
         1543                                                                  
      Leu Glu Asn Phe Asp Leu Pro Ser Ser Val Al - #a Glu Leu Phe Ile Lys      
      435                 4 - #40                 4 - #45                 4 -  
     #50                                                                       
        - - CCT GAA ATC TCA GTT GAT GAT GAT ACT GAA AC - #A GTA GAA GTC CAT    
     GAC     1591                                                              
       Pro Glu Ile Ser Val Asp Asp Asp Thr Glu Th - #r Val Glu Val His Asp     
                      455  - #               460  - #               465        
       - - AAA GTT GAA GCT TCC GAT AAA GTT GTG ACT AA - #T GAT GAA GAT GAC ACT 
         1639                                                                  
      Lys Val Glu Ala Ser Asp Lys Val Val Thr As - #n Asp Glu Asp Asp Thr      
                  470      - #           475      - #           480            
       - - GGT AAG AAA ACT AGT GTG AAG ATA GAA GCA GC - #T GCA GAA AAA GAC ATT 
         1687                                                                  
      Gly Lys Lys Thr Ser Val Lys Ile Glu Ala Al - #a Ala Glu Lys Asp Ile      
              485          - #       490          - #       495                
       - - GAC AAG AAA ACT CCC GTG AGT CCG GAA CCA GC - #T GTT ATA CCA CCT AAG 
         1735                                                                  
      Asp Lys Lys Thr Pro Val Ser Pro Glu Pro Al - #a Val Ile Pro Pro Lys      
          500              - #   505              - #   510                    
       - - AAG GTA CGC ATG GCC AAC TTG TGT GTT GTG GG - #C GGC CAT GCT GTT AAT 
         1783                                                                  
      Lys Val Arg Met Ala Asn Leu Cys Val Val Gl - #y Gly His Ala Val Asn      
      515                 5 - #20                 5 - #25                 5 -  
     #30                                                                       
        - - GGA GTT GCT GAG ATC CAT AGT GAA ATT GTG AA - #G GAG GAG GTT TTC    
     AAT     1831                                                              
       Gly Val Ala Glu Ile His Ser Glu Ile Val Ly - #s Glu Glu Val Phe Asn     
                      535  - #               540  - #               545        
       - - GAC TTC TAT GAG CTC TGG CCG GAA AAG TTC CA - #A AAC AAA ACA AAT GGA 
         1879                                                                  
      Asp Phe Tyr Glu Leu Trp Pro Glu Lys Phe Gl - #n Asn Lys Thr Asn Gly      
                  550      - #           555      - #           560            
       - - GTG ACT CCA AGA AGA TGG ATT CGT TTC TGC AA - #T CCT CCT CTT AGT GCC 
         1927                                                                  
      Val Thr Pro Arg Arg Trp Ile Arg Phe Cys As - #n Pro Pro Leu Ser Ala      
              565          - #       570          - #       575                
       - - ATC ATA ACT AAG TGG ACT GGT ACA GAG GAT TG - #G GTC CTG AAA ACT GAA 
         1975                                                                  
      Ile Ile Thr Lys Trp Thr Gly Thr Glu Asp Tr - #p Val Leu Lys Thr Glu      
          580              - #   585              - #   590                    
       - - AAG TTG GCA GAA TTG CAG AAG TTT GCT GAT AA - #T GAA GAT CTT CAA AAT 
         2023                                                                  
      Lys Leu Ala Glu Leu Gln Lys Phe Ala Asp As - #n Glu Asp Leu Gln Asn      
      595                 6 - #00                 6 - #05                 6 -  
     #10                                                                       
        - - GAG TGG AGG GAA GCA AAA AGG AGC AAC AAG AT - #T AAA GTT GTC TCC    
     TTT     2071                                                              
       Glu Trp Arg Glu Ala Lys Arg Ser Asn Lys Il - #e Lys Val Val Ser Phe     
                      615  - #               620  - #               625        
       - - CTC AAA GAA AAG ACA GGG TAT TCT GTT GTC CC - #A GAT GCA ATG TTT GAT 
         2119                                                                  
      Leu Lys Glu Lys Thr Gly Tyr Ser Val Val Pr - #o Asp Ala Met Phe Asp      
                  630      - #           635      - #           640            
       - - ATT CAG GTA AAA CGC ATT CAT GAG TAC AAG CG - #A CAA CTG TTA AAT ATC 
         2167                                                                  
      Ile Gln Val Lys Arg Ile His Glu Tyr Lys Ar - #g Gln Leu Leu Asn Ile      
              645          - #       650          - #       655                
       - - TTC GGC ATC GTT TAT CGG TAT AAG AAG ATG AA - #A GAA ATG ACA GCT GCA 
         2215                                                                  
      Phe Gly Ile Val Tyr Arg Tyr Lys Lys Met Ly - #s Glu Met Thr Ala Ala      
          660              - #   665              - #   670                    
       - - GAA AGA AAG ACT AAC TTC GTT CCT CGA GTA TG - #C ATA TTT GGG GGA AAA 
         2263                                                                  
      Glu Arg Lys Thr Asn Phe Val Pro Arg Val Cy - #s Ile Phe Gly Gly Lys      
      675                 6 - #80                 6 - #85                 6 -  
     #90                                                                       
        - - GCT TTT GCC ACA TAT GTG CAA GCC AAG AGG AT - #T GTA AAA TTT ATC    
     ACA     2311                                                              
       Ala Phe Ala Thr Tyr Val Gln Ala Lys Arg Il - #e Val Lys Phe Ile Thr     
                      695  - #               700  - #               705        
       - - GAT GTT GGT GCT ACT ATA AAT CAT GAT CCA GA - #A ATC GGT GAT CTG TTG 
         2359                                                                  
      Asp Val Gly Ala Thr Ile Asn His Asp Pro Gl - #u Ile Gly Asp Leu Leu      
                  710      - #           715      - #           720            
       - - AAG GTA GTC TTT GTG CCA GAT TAC AAT GTC AG - #T GTT GCT GAA TTG CTA 
         2407                                                                  
      Lys Val Val Phe Val Pro Asp Tyr Asn Val Se - #r Val Ala Glu Leu Leu      
              725          - #       730          - #       735                
       - - ATT CCT GCT AGC GAT CTA TCA GAA CAT ATC AG - #T ACG GCT GGA ATG GAG 
         2455                                                                  
      Ile Pro Ala Ser Asp Leu Ser Glu His Ile Se - #r Thr Ala Gly Met Glu      
          740              - #   745              - #   750                    
       - - GCC AGT GGA ACC AGT AAT ATG AAG TTT GCA AT - #G AAT GGT TGT ATC CAA 
         2503                                                                  
      Ala Ser Gly Thr Ser Asn Met Lys Phe Ala Me - #t Asn Gly Cys Ile Gln      
      755                 7 - #60                 7 - #65                 7 -  
     #70                                                                       
        - - ATT GGT ACA TTG GAT GGC GCT AAT GTT GAA AT - #A AGG GAA GAG GTT    
     GGA     2551                                                              
       Ile Gly Thr Leu Asp Gly Ala Asn Val Glu Il - #e Arg Glu Glu Val Gly     
                      775  - #               780  - #               785        
       - - GAA GAA AAC TTC TTT CTC TTT GGT GCT CAA GC - #T CAT GAA ATT GCA GGG 
         2599                                                                  
      Glu Glu Asn Phe Phe Leu Phe Gly Ala Gln Al - #a His Glu Ile Ala Gly      
                  790      - #           795      - #           800            
       - - CTT AGA AAA GAA AGA GCT GAC GGA AAG TTT GT - #A CCT GAT GAA CGT TTT 
         2647                                                                  
      Leu Arg Lys Glu Arg Ala Asp Gly Lys Phe Va - #l Pro Asp Glu Arg Phe      
              805          - #       810          - #       815                
       - - GAA GAG GTG AAG GAA TTT GTT AGA AGC GGT GC - #T TTT GGC TCT TAT AAC 
         2695                                                                  
      Glu Glu Val Lys Glu Phe Val Arg Ser Gly Al - #a Phe Gly Ser Tyr Asn      
          820              - #   825              - #   830                    
       - - TAT GAT GAC CTA ATT GGA TCG TTG GAA GGA AA - #T GAA GGT TTT GGC CGT 
         2743                                                                  
      Tyr Asp Asp Leu Ile Gly Ser Leu Glu Gly As - #n Glu Gly Phe Gly Arg      
      835                 8 - #40                 8 - #45                 8 -  
     #50                                                                       
        - - GCT GAC TAT TTC CTT GTG GGC AAG GAC TTC CC - #C AGT TAC ATA GAA    
     TGC     2791                                                              
       Ala Asp Tyr Phe Leu Val Gly Lys Asp Phe Pr - #o Ser Tyr Ile Glu Cys     
                      855  - #               860  - #               865        
       - - CAA GAG AAA GTT GAT GAG GCA TAT CGC GAC CA - #G AAA AGG TGG ACA ACG 
         2839                                                                  
      Gln Glu Lys Val Asp Glu Ala Tyr Arg Asp Gl - #n Lys Arg Trp Thr Thr      
                  870      - #           875      - #           880            
       - - ATG TCA ATC TTG AAT ACA GCG GGA TCG TAC AA - #G TTC AGC AGT GAC AGA 
         2887                                                                  
      Met Ser Ile Leu Asn Thr Ala Gly Ser Tyr Ly - #s Phe Ser Ser Asp Arg      
              885          - #       890          - #       895                
       - - ACA ATC CAT GAA TAT GCC AAA GAC ATT TGG AA - #C ATT GAA GCT GTG GAA 
         2935                                                                  
      Thr Ile His Glu Tyr Ala Lys Asp Ile Trp As - #n Ile Glu Ala Val Glu      
          900              - #   905              - #   910                    
       - - ATA GCA TAA GAGGGGGAAG TGAATGAAAA ATAACAAAGG CACAGTAAG - #T         
         2984                                                                  
      Ile Ala  *                                                               
      915                                                                      
       - - AGTTTCTCTT TTTATCATGT GATGAAGGTA TATAATGTAT GTGTAAGAGG AT -         
     #GATGTTAT   3044                                                          
        - - TACCACATAA TAAGAGATGA AGAGTCTCAT TTTGCTTCAA AAAAAAAAAA AA - #AAAAA 
          3101                                                                 
       - -  - - (2) INFORMATION FOR SEQ ID NO:2:                               
       - -      (i) SEQUENCE CHARACTERISTICS:                                  
                (A) LENGTH:  966 ami - #no acids                               
                (B) TYPE: amino acid                                           
                (D) TOPOLOGY: linear                                           
       - -     (ii) MOLECULE TYPE: protein                                     
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:                         
       - - Met Ala Thr Ala Asn Gly Ala His Leu Phe As - #n His Tyr Ser Ser Asn 
     50                 - - #45                 - - #40                 - -    
     #35                                                                       
        - - Ser Arg Phe Ile His Phe Thr Ser Arg Asn Th - #r Ser Ser Lys Leu    
     Phe                                                                       
                       -30  - #               -25  - #               -20       
       - - Leu Thr Lys Thr Ser His Phe Arg Arg Pro Ly - #s Arg Cys Phe His Val 
                  -15      - #           -10      - #            -5            
       - - Asn Asn Thr Leu Ser Glu Lys Ile His His Pr - #o Ile Thr Glu Gln Gly 
                1        - #       5           - #       10                    
       - - Gly Glu Ser Asp Leu Ser Ser Phe Ala Pro As - #p Ala Ala Ser Ile Thr 
       15                 - # 20                 - # 25                 - # 30 
       - - Ser Ser Ile Lys Tyr His Ala Glu Phe Thr Pr - #o Val Phe Ser Pro Glu 
                       35 - #                 40 - #                 45        
       - - Arg Phe Glu Leu Pro Lys Ala Phe Phe Ala Th - #r Ala Gln Ser Val Arg 
                   50     - #             55     - #             60            
       - - Asp Ser Leu Leu Ile Asn Trp Asn Ala Thr Ty - #r Asp Ile Tyr Glu Lys 
               65         - #         70         - #         75                
       - - Leu Asn Met Lys Gln Ala Tyr Tyr Leu Ser Me - #t Glu Phe Leu Gln Gly 
           80             - #     85             - #     90                    
       - - Arg Ala Leu Leu Asn Ala Ile Gly Asn Leu Gl - #u Leu Thr Gly Ala Phe 
       95                 - #100                 - #105                 - #110 
       - - Ala Glu Ala Leu Lys Asn Leu Gly His Asn Le - #u Glu Asn Val Ala Ser 
                      115  - #               120  - #               125        
       - - Gln Glu Pro Asp Ala Ala Leu Gly Asn Gly Gl - #y Leu Gly Arg Leu Ala 
                  130      - #           135      - #           140            
       - - Ser Cys Phe Leu Asp Ser Leu Ala Thr Leu As - #n Tyr Pro Ala Trp Gly 
              145          - #       150          - #       155                
       - - Tyr Gly Leu Arg Tyr Lys Tyr Gly Leu Phe Ly - #s Gln Arg Ile Thr Lys 
          160              - #   165              - #   170                    
       - - Asp Gly Gln Glu Glu Val Ala Glu Asp Trp Le - #u Glu Ile Gly Ser Pro 
      175                 1 - #80                 1 - #85                 1 -  
     #90                                                                       
        - - Trp Glu Val Val Arg Asn Asp Val Ser Tyr Pr - #o Ile Lys Phe Tyr    
     Gly                                                                       
                       195  - #               200  - #               205       
       - - Lys Val Ser Thr Gly Ser Asp Gly Lys Arg Ty - #r Trp Ile Gly Gly Glu 
                  210      - #           215      - #           220            
       - - Asp Ile Lys Ala Val Ala Tyr Asp Val Pro Il - #e Pro Gly Tyr Lys Thr 
              225          - #       230          - #       235                
       - - Arg Thr Thr Ile Ser Leu Arg Leu Trp Ser Th - #r Gln Val Pro Ser Ala 
          240              - #   245              - #   250                    
       - - Asp Phe Asp Leu Ser Ala Phe Asn Ala Gly Gl - #u His Thr Lys Ala Cys 
      255                 2 - #60                 2 - #65                 2 -  
     #70                                                                       
        - - Glu Ala Gln Ala Asn Ala Glu Lys Ile Cys Ty - #r Ile Leu Tyr Pro    
     Gly                                                                       
                       275  - #               280  - #               285       
       - - Asp Glu Ser Glu Glu Gly Lys Ile Leu Arg Le - #u Lys Gln Gln Tyr Thr 
                  290      - #           295      - #           300            
       - - Leu Cys Ser Ala Ser Leu Gln Asp Ile Ile Se - #r Arg Phe Glu Arg Arg 
              305          - #       310          - #       315                
       - - Ser Gly Asp Arg Ile Lys Trp Glu Glu Phe Pr - #o Glu Lys Val Ala Val 
          320              - #   325              - #   330                    
       - - Gln Met Asn Asp Thr His Pro Thr Leu Cys Il - #e Pro Glu Leu Met Arg 
      335                 3 - #40                 3 - #45                 3 -  
     #50                                                                       
        - - Ile Leu Ile Asp Leu Lys Gly Leu Asn Trp As - #n Glu Ala Trp Asn    
     Ile                                                                       
                       355  - #               360  - #               365       
       - - Thr Gln Arg Thr Val Ala Tyr Thr Asn His Th - #r Val Leu Pro Glu Ala 
                  370      - #           375      - #           380            
       - - Leu Glu Lys Trp Ser Tyr Glu Leu Met Gln Ly - #s Leu Leu Pro Arg His 
              385          - #       390          - #       395                
       - - Val Glu Ile Ile Glu Ala Ile Asp Glu Glu Le - #u Val His Glu Ile Val 
          400              - #   405              - #   410                    
       - - Leu Lys Tyr Gly Ser Met Asp Leu Asn Lys Le - #u Glu Glu Lys Leu Thr 
      415                 4 - #20                 4 - #25                 4 -  
     #30                                                                       
        - - Thr Met Arg Ile Leu Glu Asn Phe Asp Leu Pr - #o Ser Ser Val Ala    
     Glu                                                                       
                       435  - #               440  - #               445       
       - - Leu Phe Ile Lys Pro Glu Ile Ser Val Asp As - #p Asp Thr Glu Thr Val 
                  450      - #           455      - #           460            
       - - Glu Val His Asp Lys Val Glu Ala Ser Asp Ly - #s Val Val Thr Asn Asp 
              465          - #       470          - #       475                
       - - Glu Asp Asp Thr Gly Lys Lys Thr Ser Val Ly - #s Ile Glu Ala Ala Ala 
          480              - #   485              - #   490                    
       - - Glu Lys Asp Ile Asp Lys Lys Thr Pro Val Se - #r Pro Glu Pro Ala Val 
      495                 5 - #00                 5 - #05                 5 -  
     #10                                                                       
        - - Ile Pro Pro Lys Lys Val Arg Met Ala Asn Le - #u Cys Val Val Gly    
     Gly                                                                       
                       515  - #               520  - #               525       
       - - His Ala Val Asn Gly Val Ala Glu Ile His Se - #r Glu Ile Val Lys Glu 
                  530      - #           535      - #           540            
       - - Glu Val Phe Asn Asp Phe Tyr Glu Leu Trp Pr - #o Glu Lys Phe Gln Asn 
              545          - #       550          - #       555                
       - - Lys Thr Asn Gly Val Thr Pro Arg Arg Trp Il - #e Arg Phe Cys Asn Pro 
          560              - #   565              - #   570                    
       - - Pro Leu Ser Ala Ile Ile Thr Lys Trp Thr Gl - #y Thr Glu Asp Trp Val 
      575                 5 - #80                 5 - #85                 5 -  
     #90                                                                       
        - - Leu Lys Thr Glu Lys Leu Ala Glu Leu Gln Ly - #s Phe Ala Asp Asn    
     Glu                                                                       
                       595  - #               600  - #               605       
       - - Asp Leu Gln Asn Glu Trp Arg Glu Ala Lys Ar - #g Ser Asn Lys Ile Lys 
                  610      - #           615      - #           620            
       - - Val Val Ser Phe Leu Lys Glu Lys Thr Gly Ty - #r Ser Val Val Pro Asp 
              625          - #       630          - #       635                
       - - Ala Met Phe Asp Ile Gln Val Lys Arg Ile Hi - #s Glu Tyr Lys Arg Gln 
          640              - #   645              - #   650                    
       - - Leu Leu Asn Ile Phe Gly Ile Val Tyr Arg Ty - #r Lys Lys Met Lys Glu 
      655                 6 - #60                 6 - #65                 6 -  
     #70                                                                       
        - - Met Thr Ala Ala Glu Arg Lys Thr Asn Phe Va - #l Pro Arg Val Cys    
     Ile                                                                       
                       675  - #               680  - #               685       
       - - Phe Gly Gly Lys Ala Phe Ala Thr Tyr Val Gl - #n Ala Lys Arg Ile Val 
                  690      - #           695      - #           700            
       - - Lys Phe Ile Thr Asp Val Gly Ala Thr Ile As - #n His Asp Pro Glu Ile 
              705          - #       710          - #       715                
       - - Gly Asp Leu Leu Lys Val Val Phe Val Pro As - #p Tyr Asn Val Ser Val 
          720              - #   725              - #   730                    
       - - Ala Glu Leu Leu Ile Pro Ala Ser Asp Leu Se - #r Glu His Ile Ser Thr 
      735                 7 - #40                 7 - #45                 7 -  
     #50                                                                       
        - - Ala Gly Met Glu Ala Ser Gly Thr Ser Asn Me - #t Lys Phe Ala Met    
     Asn                                                                       
                       755  - #               760  - #               765       
       - - Gly Cys Ile Gln Ile Gly Thr Leu Asp Gly Al - #a Asn Val Glu Ile Arg 
                  770      - #           775      - #           780            
       - - Glu Glu Val Gly Glu Glu Asn Phe Phe Leu Ph - #e Gly Ala Gln Ala His 
              785          - #       790          - #       795                
       - - Glu Ile Ala Gly Leu Arg Lys Glu Arg Ala As - #p Gly Lys Phe Val Pro 
          800              - #   805              - #   810                    
       - - Asp Glu Arg Phe Glu Glu Val Lys Glu Phe Va - #l Arg Ser Gly Ala Phe 
      815                 8 - #20                 8 - #25                 8 -  
     #30                                                                       
        - - Gly Ser Tyr Asn Tyr Asp Asp Leu Ile Gly Se - #r Leu Glu Gly Asn    
     Glu                                                                       
                       835  - #               840  - #               845       
       - - Gly Phe Gly Arg Ala Asp Tyr Phe Leu Val Gl - #y Lys Asp Phe Pro Ser 
                  850      - #           855      - #           860            
       - - Tyr Ile Glu Cys Gln Glu Lys Val Asp Glu Al - #a Tyr Arg Asp Gln Lys 
              865          - #       870          - #       875                
       - - Arg Trp Thr Thr Met Ser Ile Leu Asn Thr Al - #a Gly Ser Tyr Lys Phe 
          880              - #   885              - #   890                    
       - - Ser Ser Asp Arg Thr Ile His Glu Tyr Ala Ly - #s Asp Ile Trp Asn Ile 
      895                 9 - #00                 9 - #05                 9 -  
     #10                                                                       
        - - Glu Ala Val Glu Ile Ala                                            
                       915                                                     
        - -  - - (2) INFORMATION FOR SEQ ID NO:3:                              
        - -      (i) SEQUENCE CHARACTERISTICS:                                 
                 (A) LENGTH: 2655 base - #pairs                                
                 (B) TYPE: nucleic acid                                        
                 (C) STRANDEDNESS: double                                      
                 (D) TOPOLOGY: linear                                          
        - -     (ii) MOLECULE TYPE: DNA (genomic)                              
        - -    (iii) HYPOTHETICAL: NO                                          
        - -     (iv) ANTI-SENSE: NO                                            
        - -     (vi) ORIGINAL SOURCE:                                          
                 (A) ORGANISM: Solanum t - #uberosum                           
        - -     (ix) FEATURE:                                                  
                 (A) NAME/KEY: CDS                                             
                 (B) LOCATION: 12..2528                                        
                 (D) OTHER INFORMATION: - #/product= "potato alpha-glucan      
                     H-type tu - #ber phosphorylase"                           
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: mat.sub.-- - #peptide                            
                (B) LOCATION: 12..2525                                         
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:                         
       - - GTTTATTTTC C ATG GAA GGT GGT GCA AAA TCG AAT - #GAT GTA TCA GCA GCA 
          50                                                                   
                   Met Glu Gly - #Gly Ala Lys Ser Asn Asp Val Ser Ala Ala      
                     1   - #            5      - #            10               
       - - CCT ATT GCT CAA CCA CTT TCT GAA GAC CCT AC - #T GAC ATT GCA TCT AAT 
           98                                                                  
      Pro Ile Ala Gln Pro Leu Ser Glu Asp Pro Th - #r Asp Ile Ala Ser Asn      
           15             - #     20             - #     25                    
       - - ATC AAG TAT CAT GCT CAA TAT ACT CCT CAT TT - #T TCT CCT TTC AAG TTT 
          146                                                                  
      Ile Lys Tyr His Ala Gln Tyr Thr Pro His Ph - #e Ser Pro Phe Lys Phe      
       30                 - # 35                 - # 40                 - # 45 
       - - GAG CCA CTA CAA GCA TAC TAT GCT GCT ACT GC - #T GAC AGT GTT CGT GAT 
          194                                                                  
      Glu Pro Leu Gln Ala Tyr Tyr Ala Ala Thr Al - #a Asp Ser Val Arg Asp      
                       50 - #                 55 - #                 60        
       - - CGC TTG ATC AAA CAA TGG AAT GAC ACC TAT CT - #T CAT TAT GAC AAA GTT 
          242                                                                  
      Arg Leu Ile Lys Gln Trp Asn Asp Thr Tyr Le - #u His Tyr Asp Lys Val      
                   65     - #             70     - #             75            
       - - AAT CCA AAG CAA ACA TAC TAC TTA TCA ATG GA - #G TAT CTC CAG GGG CGA 
          290                                                                  
      Asn Pro Lys Gln Thr Tyr Tyr Leu Ser Met Gl - #u Tyr Leu Gln Gly Arg      
               80         - #         85         - #         90                
       - - GCT TTG ACA AAT GCA GTT GGA AAC TTA GAC AT - #C CAC AAT GCA TAT GCT 
          338                                                                  
      Ala Leu Thr Asn Ala Val Gly Asn Leu Asp Il - #e His Asn Ala Tyr Ala      
           95             - #    100             - #    105                    
       - - GAT GCT TTA AAC AAA CTG GGT CAG CAG CTT GA - #G GAG GTC GTT GAG CAG 
          386                                                                  
      Asp Ala Leu Asn Lys Leu Gly Gln Gln Leu Gl - #u Glu Val Val Glu Gln      
      110                 1 - #15                 1 - #20                 1 -  
     #25                                                                       
        - - GAA AAA GAT GCA GCA TTA GGA AAT GGT GGT TT - #A GGA AGG CTC GCT    
     TCA      434                                                              
       Glu Lys Asp Ala Ala Leu Gly Asn Gly Gly Le - #u Gly Arg Leu Ala Ser     
                      130  - #               135  - #               140        
       - - TGC TTT CTT GAT TCC ATG GCC ACA TTG AAC CT - #T CCA GCA TGG GGT TAT 
          482                                                                  
      Cys Phe Leu Asp Ser Met Ala Thr Leu Asn Le - #u Pro Ala Trp Gly Tyr      
                  145      - #           150      - #           155            
       - - GGC TTG AGG TAC AGA TAT GGA CTT TTT AAG CA - #G CTT ATC ACA AAG GCT 
          530                                                                  
      Gly Leu Arg Tyr Arg Tyr Gly Leu Phe Lys Gl - #n Leu Ile Thr Lys Ala      
              160          - #       165          - #       170                
       - - GGG CAA GAA GAA GTT CCT GAA GAT TGG TTG GA - #G AAA TTT AGT CCC TGG 
          578                                                                  
      Gly Gln Glu Glu Val Pro Glu Asp Trp Leu Gl - #u Lys Phe Ser Pro Trp      
          175              - #   180              - #   185                    
       - - GAA ATT GTA AGG CAT GAT GTT GTC TTT CCT AT - #C AGG TTT TTT GGT CAT 
          626                                                                  
      Glu Ile Val Arg His Asp Val Val Phe Pro Il - #e Arg Phe Phe Gly His      
      190                 1 - #95                 2 - #00                 2 -  
     #05                                                                       
        - - GTT GAA GTC CTC CCT TCT GGC TCG CGA AAA TG - #G GTT GGT GGA GAG    
     GTC      674                                                              
       Val Glu Val Leu Pro Ser Gly Ser Arg Lys Tr - #p Val Gly Gly Glu Val     
                      210  - #               215  - #               220        
       - - CTA CAG GCT CTT GCA TAT GAT GTG CCA ATT CC - #A GGA TAC AGA ACT AAA 
          722                                                                  
      Leu Gln Ala Leu Ala Tyr Asp Val Pro Ile Pr - #o Gly Tyr Arg Thr Lys      
                  225      - #           230      - #           235            
       - - AAC ACT AAT AGT CTT CGT CTC TGG GAA GCC AA - #A GCA AGC TCT GAG GAT 
          770                                                                  
      Asn Thr Asn Ser Leu Arg Leu Trp Glu Ala Ly - #s Ala Ser Ser Glu Asp      
              240          - #       245          - #       250                
       - - TTC AAC TTG TTT CTG TTT AAT GAT GGA CAG TA - #T GAT GCT GCT GCA CAG 
          818                                                                  
      Phe Asn Leu Phe Leu Phe Asn Asp Gly Gln Ty - #r Asp Ala Ala Ala Gln      
          255              - #   260              - #   265                    
       - - CTT CAT TCT AGG GCT CAG CAG ATT TGT GCT GT - #T CTC TAC CCT GGG GAT 
          866                                                                  
      Leu His Ser Arg Ala Gln Gln Ile Cys Ala Va - #l Leu Tyr Pro Gly Asp      
      270                 2 - #75                 2 - #80                 2 -  
     #85                                                                       
        - - GCT ACA GAG AAT GGA AAA CTC TTA CGG CTA AA - #G CAA CAA TTT TTT    
     CTG      914                                                              
       Ala Thr Glu Asn Gly Lys Leu Leu Arg Leu Ly - #s Gln Gln Phe Phe Leu     
                      290  - #               295  - #               300        
       - - TGC AGT GCA TCG CTT CAG GAT ATT ATT GCC AG - #A TTC AAA GAG AGA GAA 
          962                                                                  
      Cys Ser Ala Ser Leu Gln Asp Ile Ile Ala Ar - #g Phe Lys Glu Arg Glu      
                  305      - #           310      - #           315            
       - - GAT GGA AAG GGT TCT CAC CAG TGG TCT GAA TT - #C CCC AAG AAG GTT GCG 
         1010                                                                  
      Asp Gly Lys Gly Ser His Gln Trp Ser Glu Ph - #e Pro Lys Lys Val Ala      
              320          - #       325          - #       330                
       - - ATA CAA CTA AAT GAC ACA CAT CCA ACT CTT AC - #G ATT CCA GAG CTG ATG 
         1058                                                                  
      Ile Gln Leu Asn Asp Thr His Pro Thr Leu Th - #r Ile Pro Glu Leu Met      
          335              - #   340              - #   345                    
       - - CGG TTG CTA ATG GAT GAT GAA GGA CTT GGG TG - #G GAT GAA TCT TGG AAT 
         1106                                                                  
      Arg Leu Leu Met Asp Asp Glu Gly Leu Gly Tr - #p Asp Glu Ser Trp Asn      
      350                 3 - #55                 3 - #60                 3 -  
     #65                                                                       
        - - ATC ACT ACT AGG ACA ATT GCC TAT ACG AAT CA - #T ACA GTC CTA CCT    
     GAA     1154                                                              
       Ile Thr Thr Arg Thr Ile Ala Tyr Thr Asn Hi - #s Thr Val Leu Pro Glu     
                      370  - #               375  - #               380        
       - - GCA CTT GAA AAA TGG TCT CAG GCA GTC ATG TG - #G AAG CTC CTT CCT AGA 
         1202                                                                  
      Ala Leu Glu Lys Trp Ser Gln Ala Val Met Tr - #p Lys Leu Leu Pro Arg      
                  385      - #           390      - #           395            
       - - CAT ATG GAA ATC ATT GAA GAA ATT GAC AAA CG - #G TTT GTT GCT ACA ATA 
         1250                                                                  
      His Met Glu Ile Ile Glu Glu Ile Asp Lys Ar - #g Phe Val Ala Thr Ile      
              400          - #       405          - #       410                
       - - ATG TCA GAA AGA CCT GAT CTT GAG AAT AAG AT - #G CCT AGC ATG CGC ATT 
         1298                                                                  
      Met Ser Glu Arg Pro Asp Leu Glu Asn Lys Me - #t Pro Ser Met Arg Ile      
          415              - #   420              - #   425                    
       - - TTG GAT CAC AAC GCC ACA AAA CCT GTT GTG CA - #T ATG GCT AAC TTG TGT 
         1346                                                                  
      Leu Asp His Asn Ala Thr Lys Pro Val Val Hi - #s Met Ala Asn Leu Cys      
      430                 4 - #35                 4 - #40                 4 -  
     #45                                                                       
        - - GTT GTC TCT TCA CAT ACG GTA AAT GGT GTT GC - #C CAG CTG CAT AGT    
     GAC     1394                                                              
       Val Val Ser Ser His Thr Val Asn Gly Val Al - #a Gln Leu His Ser Asp     
                      450  - #               455  - #               460        
       - - ATC CTG AAG GCT GAG TTA TTT GCT GAT TAT GT - #C TCT GTA TGG CCC ACC 
         1442                                                                  
      Ile Leu Lys Ala Glu Leu Phe Ala Asp Tyr Va - #l Ser Val Trp Pro Thr      
                  465      - #           470      - #           475            
       - - AAG TTC CAG AAT AAG ACC AAT GGT ATA ACT CC - #T CGT AGG TGG ATC CGA 
         1490                                                                  
      Lys Phe Gln Asn Lys Thr Asn Gly Ile Thr Pr - #o Arg Arg Trp Ile Arg      
              480          - #       485          - #       490                
       - - TTT TGT AGT CCT GAG CTG AGT CAT ATA ATT AC - #C AAG TGG TTA AAA ACA 
         1538                                                                  
      Phe Cys Ser Pro Glu Leu Ser His Ile Ile Th - #r Lys Trp Leu Lys Thr      
          495              - #   500              - #   505                    
       - - GAT CAA TGG GTG ACG AAC CTC GAA CTG CTT GC - #T AAT CTT CGG GAG TTT 
         1586                                                                  
      Asp Gln Trp Val Thr Asn Leu Glu Leu Leu Al - #a Asn Leu Arg Glu Phe      
      510                 5 - #15                 5 - #20                 5 -  
     #25                                                                       
        - - GCT GAT AAT TCG GAG CTC CAT GCT GAA TGG GA - #A TCA GCC AAG ATG    
     GCC     1634                                                              
       Ala Asp Asn Ser Glu Leu His Ala Glu Trp Gl - #u Ser Ala Lys Met Ala     
                      530  - #               535  - #               540        
       - - AAC AAG CAG CGT TTG GCA CAG TAT ATA CTG CA - #T GTG ACA GGT GTG AGC 
         1682                                                                  
      Asn Lys Gln Arg Leu Ala Gln Tyr Ile Leu Hi - #s Val Thr Gly Val Ser      
                  545      - #           550      - #           555            
       - - ATC GAT CCA AAT TCC CTT TTT GAC ATA CAA GT - #C AAA CGT ATC CAT GAA 
         1730                                                                  
      Ile Asp Pro Asn Ser Leu Phe Asp Ile Gln Va - #l Lys Arg Ile His Glu      
              560          - #       565          - #       570                
       - - TAC AAA AGG CAG CTT CTA AAT ATT CTG GGC GT - #C ATC TAT AGA TAC AAG 
         1778                                                                  
      Tyr Lys Arg Gln Leu Leu Asn Ile Leu Gly Va - #l Ile Tyr Arg Tyr Lys      
          575              - #   580              - #   585                    
       - - AAG CTT AAG GGA ATG AGC CCT GAA GAA AGG AA - #A AAT ACA ACT CCT CGC 
         1826                                                                  
      Lys Leu Lys Gly Met Ser Pro Glu Glu Arg Ly - #s Asn Thr Thr Pro Arg      
      590                 5 - #95                 6 - #00                 6 -  
     #05                                                                       
        - - ACA GTC ATG ATT GGA GGA AAA GCA TTT GCA AC - #A TAC ACA AAT GCA    
     AAA     1874                                                              
       Thr Val Met Ile Gly Gly Lys Ala Phe Ala Th - #r Tyr Thr Asn Ala Lys     
                      610  - #               615  - #               620        
       - - CGA ATT GTC AAG CTC GTG ACT GAT GTT GGC GA - #C GTT GTC AAT AGT GAC 
         1922                                                                  
      Arg Ile Val Lys Leu Val Thr Asp Val Gly As - #p Val Val Asn Ser Asp      
                  625      - #           630      - #           635            
       - - CCT GAC GTC AAT GAC TAT TTG AAG GTG GTT TT - #T GTT CCC AAC TAC AAT 
         1970                                                                  
      Pro Asp Val Asn Asp Tyr Leu Lys Val Val Ph - #e Val Pro Asn Tyr Asn      
              640          - #       645          - #       650                
       - - GTA TCT GTG GCA GAG ATG CTT ATT CCG GGA AG - #T GAG CTA TCA CAA CAC 
         2018                                                                  
      Val Ser Val Ala Glu Met Leu Ile Pro Gly Se - #r Glu Leu Ser Gln His      
          655              - #   660              - #   665                    
       - - ATC AGT ACT GCA GGC ATG GAA GCA AGT GGA AC - #A AGC AAC ATG AAA TTT 
         2066                                                                  
      Ile Ser Thr Ala Gly Met Glu Ala Ser Gly Th - #r Ser Asn Met Lys Phe      
      670                 6 - #75                 6 - #80                 6 -  
     #85                                                                       
        - - GCC CTT AAT GGA TGC CTT ATC ATT GGG ACA CT - #A GAT GGG GCC AAT    
     GTG     2114                                                              
       Ala Leu Asn Gly Cys Leu Ile Ile Gly Thr Le - #u Asp Gly Ala Asn Val     
                      690  - #               695  - #               700        
       - - GAA ATT AGG GAG GAA ATT GGA GAA GAT AAC TT - #C TTT CTT TTT GGT GCA 
         2162                                                                  
      Glu Ile Arg Glu Glu Ile Gly Glu Asp Asn Ph - #e Phe Leu Phe Gly Ala      
                  705      - #           710      - #           715            
       - - ACA GCT GAT GAA GTT CCT CAA CTG CGC AAA GA - #T CGA GAG AAT GGA CTG 
         2210                                                                  
      Thr Ala Asp Glu Val Pro Gln Leu Arg Lys As - #p Arg Glu Asn Gly Leu      
              720          - #       725          - #       730                
       - - TTC AAA CCT GAT CCT CGG TTT GAA GAG GCA AA - #A CAA TTT ATT AGG TCT 
         2258                                                                  
      Phe Lys Pro Asp Pro Arg Phe Glu Glu Ala Ly - #s Gln Phe Ile Arg Ser      
          735              - #   740              - #   745                    
       - - GGA GCA TTT GGG ACG TAT GAT TAT AAT CCC CT - #C CTT GAA TCA CTG GAA 
         2306                                                                  
      Gly Ala Phe Gly Thr Tyr Asp Tyr Asn Pro Le - #u Leu Glu Ser Leu Glu      
      750                 7 - #55                 7 - #60                 7 -  
     #65                                                                       
        - - GGG AAC TCG GGA TAT GGT CGT GGA GAC TAT TT - #T CTT GTT GGT CAT    
     GAT     2354                                                              
       Gly Asn Ser Gly Tyr Gly Arg Gly Asp Tyr Ph - #e Leu Val Gly His Asp     
                      770  - #               775  - #               780        
       - - TTT CCG AGC TAC ATG GAT GCT CAG GCA AGG GT - #T GAT GAA GCT TAC AAG 
         2402                                                                  
      Phe Pro Ser Tyr Met Asp Ala Gln Ala Arg Va - #l Asp Glu Ala Tyr Lys      
                  785      - #           790      - #           795            
       - - GAC AGG AAA AGA TGG ATA AAG ATG TCT ATA CT - #G AGC ACT AGT GGG AGT 
         2450                                                                  
      Asp Arg Lys Arg Trp Ile Lys Met Ser Ile Le - #u Ser Thr Ser Gly Ser      
              800          - #       805          - #       810                
       - - GGC AAA TTT AGT AGT GAC CGT ACA ATT TCT CA - #A TAT GCA AAA GAG ATC 
         2498                                                                  
      Gly Lys Phe Ser Ser Asp Arg Thr Ile Ser Gl - #n Tyr Ala Lys Glu Ile      
          815              - #   820              - #   825                    
       - - TGG AAC ATT GCC GAG TGT CGC GTG CCT TGA GC - #ACACTTCT GAACCTGGTA   
         2548                                                                  
      Trp Asn Ile Ala Glu Cys Arg Val Pro  *                                   
      830                 8 - #35                                              
       - - TCTAATAAGG ATCTAATGTT CATTGTTTAC TAGCATATGA ATAATGTAAG TT -         
     #CAAGCACA   2608                                                          
        - - ACATGCTTTC TTATTTCCTA CTGCTCTCAA GAAGCAGTTA TTTGTTG   - #          
         2655                                                                  
       - -  - - (2) INFORMATION FOR SEQ ID NO:4:                               
       - -      (i) SEQUENCE CHARACTERISTICS:                                  
                (A) LENGTH:  838 ami - #no acids                               
                (B) TYPE: amino acid                                           
                (D) TOPOLOGY: linear                                           
       - -     (ii) MOLECULE TYPE: protein                                     
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:                         
       - - Met Glu Gly Gly Ala Lys Ser Asn Asp Val Se - #r Ala Ala Pro Ile Ala 
        1               5 - #                 10 - #                 15        
       - - Gln Pro Leu Ser Glu Asp Pro Thr Asp Ile Al - #a Ser Asn Ile Lys Tyr 
                   20     - #             25     - #             30            
       - - His Ala Gln Tyr Thr Pro His Phe Ser Pro Ph - #e Lys Phe Glu Pro Leu 
               35         - #         40         - #         45                
       - - Gln Ala Tyr Tyr Ala Ala Thr Ala Asp Ser Va - #l Arg Asp Arg Leu Ile 
           50             - #     55             - #     60                    
       - - Lys Gln Trp Asn Asp Thr Tyr Leu His Tyr As - #p Lys Val Asn Pro Lys 
       65                 - # 70                 - # 75                 - # 80 
       - - Gln Thr Tyr Tyr Leu Ser Met Glu Tyr Leu Gl - #n Gly Arg Ala Leu Thr 
                       85 - #                 90 - #                 95        
       - - Asn Ala Val Gly Asn Leu Asp Ile His Asn Al - #a Tyr Ala Asp Ala Leu 
                  100      - #           105      - #           110            
       - - Asn Lys Leu Gly Gln Gln Leu Glu Glu Val Va - #l Glu Gln Glu Lys Asp 
              115          - #       120          - #       125                
       - - Ala Ala Leu Gly Asn Gly Gly Leu Gly Arg Le - #u Ala Ser Cys Phe Leu 
          130              - #   135              - #   140                    
       - - Asp Ser Met Ala Thr Leu Asn Leu Pro Ala Tr - #p Gly Tyr Gly Leu Arg 
      145                 1 - #50                 1 - #55                 1 -  
     #60                                                                       
        - - Tyr Arg Tyr Gly Leu Phe Lys Gln Leu Ile Th - #r Lys Ala Gly Gln    
     Glu                                                                       
                       165  - #               170  - #               175       
       - - Glu Val Pro Glu Asp Trp Leu Glu Lys Phe Se - #r Pro Trp Glu Ile Val 
                  180      - #           185      - #           190            
       - - Arg His Asp Val Val Phe Pro Ile Arg Phe Ph - #e Gly His Val Glu Val 
              195          - #       200          - #       205                
       - - Leu Pro Ser Gly Ser Arg Lys Trp Val Gly Gl - #y Glu Val Leu Gln Ala 
          210              - #   215              - #   220                    
       - - Leu Ala Tyr Asp Val Pro Ile Pro Gly Tyr Ar - #g Thr Lys Asn Thr Asn 
      225                 2 - #30                 2 - #35                 2 -  
     #40                                                                       
        - - Ser Leu Arg Leu Trp Glu Ala Lys Ala Ser Se - #r Glu Asp Phe Asn    
     Leu                                                                       
                       245  - #               250  - #               255       
       - - Phe Leu Phe Asn Asp Gly Gln Tyr Asp Ala Al - #a Ala Gln Leu His Ser 
                  260      - #           265      - #           270            
       - - Arg Ala Gln Gln Ile Cys Ala Val Leu Tyr Pr - #o Gly Asp Ala Thr Glu 
              275          - #       280          - #       285                
       - - Asn Gly Lys Leu Leu Arg Leu Lys Gln Gln Ph - #e Phe Leu Cys Ser Ala 
          290              - #   295              - #   300                    
       - - Ser Leu Gln Asp Ile Ile Ala Arg Phe Lys Gl - #u Arg Glu Asp Gly Lys 
      305                 3 - #10                 3 - #15                 3 -  
     #20                                                                       
        - - Gly Ser His Gln Trp Ser Glu Phe Pro Lys Ly - #s Val Ala Ile Gln    
     Leu                                                                       
                       325  - #               330  - #               335       
       - - Asn Asp Thr His Pro Thr Leu Thr Ile Pro Gl - #u Leu Met Arg Leu Leu 
                  340      - #           345      - #           350            
       - - Met Asp Asp Glu Gly Leu Gly Trp Asp Glu Se - #r Trp Asn Ile Thr Thr 
              355          - #       360          - #       365                
       - - Arg Thr Ile Ala Tyr Thr Asn His Thr Val Le - #u Pro Glu Ala Leu Glu 
          370              - #   375              - #   380                    
       - - Lys Trp Ser Gln Ala Val Met Trp Lys Leu Le - #u Pro Arg His Met Glu 
      385                 3 - #90                 3 - #95                 4 -  
     #00                                                                       
        - - Ile Ile Glu Glu Ile Asp Lys Arg Phe Val Al - #a Thr Ile Met Ser    
     Glu                                                                       
                       405  - #               410  - #               415       
       - - Arg Pro Asp Leu Glu Asn Lys Met Pro Ser Me - #t Arg Ile Leu Asp His 
                  420      - #           425      - #           430            
       - - Asn Ala Thr Lys Pro Val Val His Met Ala As - #n Leu Cys Val Val Ser 
              435          - #       440          - #       445                
       - - Ser His Thr Val Asn Gly Val Ala Gln Leu Hi - #s Ser Asp Ile Leu Lys 
          450              - #   455              - #   460                    
       - - Ala Glu Leu Phe Ala Asp Tyr Val Ser Val Tr - #p Pro Thr Lys Phe Gln 
      465                 4 - #70                 4 - #75                 4 -  
     #80                                                                       
        - - Asn Lys Thr Asn Gly Ile Thr Pro Arg Arg Tr - #p Ile Arg Phe Cys    
     Ser                                                                       
                       485  - #               490  - #               495       
       - - Pro Glu Leu Ser His Ile Ile Thr Lys Trp Le - #u Lys Thr Asp Gln Trp 
                  500      - #           505      - #           510            
       - - Val Thr Asn Leu Glu Leu Leu Ala Asn Leu Ar - #g Glu Phe Ala Asp Asn 
              515          - #       520          - #       525                
       - - Ser Glu Leu His Ala Glu Trp Glu Ser Ala Ly - #s Met Ala Asn Lys Gln 
          530              - #   535              - #   540                    
       - - Arg Leu Ala Gln Tyr Ile Leu His Val Thr Gl - #y Val Ser Ile Asp Pro 
      545                 5 - #50                 5 - #55                 5 -  
     #60                                                                       
        - - Asn Ser Leu Phe Asp Ile Gln Val Lys Arg Il - #e His Glu Tyr Lys    
     Arg                                                                       
                       565  - #               570  - #               575       
       - - Gln Leu Leu Asn Ile Leu Gly Val Ile Tyr Ar - #g Tyr Lys Lys Leu Lys 
                  580      - #           585      - #           590            
       - - Gly Met Ser Pro Glu Glu Arg Lys Asn Thr Th - #r Pro Arg Thr Val Met 
              595          - #       600          - #       605                
       - - Ile Gly Gly Lys Ala Phe Ala Thr Tyr Thr As - #n Ala Lys Arg Ile Val 
          610              - #   615              - #   620                    
       - - Lys Leu Val Thr Asp Val Gly Asp Val Val As - #n Ser Asp Pro Asp Val 
      625                 6 - #30                 6 - #35                 6 -  
     #40                                                                       
        - - Asn Asp Tyr Leu Lys Val Val Phe Val Pro As - #n Tyr Asn Val Ser    
     Val                                                                       
                       645  - #               650  - #               655       
       - - Ala Glu Met Leu Ile Pro Gly Ser Glu Leu Se - #r Gln His Ile Ser Thr 
                  660      - #           665      - #           670            
       - - Ala Gly Met Glu Ala Ser Gly Thr Ser Asn Me - #t Lys Phe Ala Leu Asn 
              675          - #       680          - #       685                
       - - Gly Cys Leu Ile Ile Gly Thr Leu Asp Gly Al - #a Asn Val Glu Ile Arg 
          690              - #   695              - #   700                    
       - - Glu Glu Ile Gly Glu Asp Asn Phe Phe Leu Ph - #e Gly Ala Thr Ala Asp 
      705                 7 - #10                 7 - #15                 7 -  
     #20                                                                       
        - - Glu Val Pro Gln Leu Arg Lys Asp Arg Glu As - #n Gly Leu Phe Lys    
     Pro                                                                       
                       725  - #               730  - #               735       
       - - Asp Pro Arg Phe Glu Glu Ala Lys Gln Phe Il - #e Arg Ser Gly Ala Phe 
                  740      - #           745      - #           750            
       - - Gly Thr Tyr Asp Tyr Asn Pro Leu Leu Glu Se - #r Leu Glu Gly Asn Ser 
              755          - #       760          - #       765                
       - - Gly Tyr Gly Arg Gly Asp Tyr Phe Leu Val Gl - #y His Asp Phe Pro Ser 
          770              - #   775              - #   780                    
       - - Tyr Met Asp Ala Gln Ala Arg Val Asp Glu Al - #a Tyr Lys Asp Arg Lys 
      785                 7 - #90                 7 - #95                 8 -  
     #00                                                                       
        - - Arg Trp Ile Lys Met Ser Ile Leu Ser Thr Se - #r Gly Ser Gly Lys    
     Phe                                                                       
                       805  - #               810  - #               815       
       - - Ser Ser Asp Arg Thr Ile Ser Gln Tyr Ala Ly - #s Glu Ile Trp Asn Ile 
                  820      - #           825      - #           830            
       - - Ala Glu Cys Arg Val Pro                                             
              835                                                              
       - -  - - (2) INFORMATION FOR SEQ ID NO:5:                               
       - -      (i) SEQUENCE CHARACTERISTICS:                                  
                (A) LENGTH: 3171 base - #pairs                                 
                (B) TYPE: nucleic acid                                         
                (C) STRANDEDNESS: double                                       
                (D) TOPOLOGY: linear                                           
       - -     (ii) MOLECULE TYPE: DNA (genomic)                               
       - -    (iii) HYPOTHETICAL: NO                                           
       - -     (iv) ANTI-SENSE: NO                                             
       - -     (vi) ORIGINAL SOURCE:                                           
                (A) ORGANISM: Solanum t - #uberosum                            
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: CDS                                              
                (B) LOCATION: 87..3011                                         
                (D) OTHER INFORMATION: - #/product= "potato alpha-glucan       
                     L-type le - #af phosphorylase"                            
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: mat.sub.-- - #peptide                            
                (B) LOCATION: 330..3008                                        
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: sig.sub.-- - #peptide                            
                (B) LOCATION: 87..329                                          
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:                         
       - - TTTTTTTTTT CAACATGCAC AACAATTATT TTGATTAAAT TTTGTATCTA AA -         
     #AATTTAGC     60                                                          
        - - ATTTTGAAAT TCAGTTCAGA GACATC ATG GCA ACT TTT GCT - #GTC TCT GGA    
     TTG     113                                                               
                         - #           Met Ala Thr Phe - #Ala Val Ser Gly Leu  
                        - #           -81 -80     - #            -75           
       - - AAC TCA ATT TCA AGT ATT TCT AGT TTT AAT AA - #C AAT TTC AGA AGC AAA 
          161                                                                  
      Asn Ser Ile Ser Ser Ile Ser Ser Phe Asn As - #n Asn Phe Arg Ser Lys      
              -70          - #       -65          - #       -60                
       - - AAC TCA AAC ATT TTG TTG AGT AGA AGG AGG AT - #T TTA TTG TTC AGT TTT 
          209                                                                  
      Asn Ser Asn Ile Leu Leu Ser Arg Arg Arg Il - #e Leu Leu Phe Ser Phe      
          -55              - #   -50              - #   -45                    
       - - AGA AGA AGA AGA AGA AGT TTC TCT GTT AGC AG - #T GTT GCT AGT GAT CAA 
          257                                                                  
      Arg Arg Arg Arg Arg Ser Phe Ser Val Ser Se - #r Val Ala Ser Asp Gln      
     40                 - - #35                 - - #30                 - -    
     #25                                                                       
        - - AAG CAG AAG ACA AAG GAT TCT TCC TCT GAT GA - #A GGA TTT ACA TTA    
     GAT      305                                                              
       Lys Gln Lys Thr Lys Asp Ser Ser Ser Asp Gl - #u Gly Phe Thr Leu Asp     
                      -20  - #               -15  - #               -10        
       - - GTT TTT CAG CCG GAC TCC ACG TCT GTT TTA TC - #A AGT ATA AAG TAT CAC 
          353                                                                  
      Val Phe Gln Pro Asp Ser Thr Ser Val Leu Se - #r Ser Ile Lys Tyr His      
                   -5     - #              1    - #           5                
       - - GCT GAG TTC ACA CCA TCA TTT TCT CCT GAG AA - #G TTT GAA CTT CCC AAG 
          401                                                                  
      Ala Glu Phe Thr Pro Ser Phe Ser Pro Glu Ly - #s Phe Glu Leu Pro Lys      
           10             - #     15             - #     20                    
       - - GCA TAC TAT GCA ACT GCA GAG AGT GTT CGA GA - #T ACG CTC ATT ATA AAT 
          449                                                                  
      Ala Tyr Tyr Ala Thr Ala Glu Ser Val Arg As - #p Thr Leu Ile Ile Asn      
       25                 - # 30                 - # 35                 - # 40 
       - - TGG AAT GCC ACA TAC GAA TTC TAT GAA AAG AT - #G AAT GTA AAG CAG GCA 
          497                                                                  
      Trp Asn Ala Thr Tyr Glu Phe Tyr Glu Lys Me - #t Asn Val Lys Gln Ala      
                       45 - #                 50 - #                 55        
       - - TAT TAC TTG TCT ATG GAA TTT CTT CAG GGA AG - #A GCT TTA CTC AAT GCT 
          545                                                                  
      Tyr Tyr Leu Ser Met Glu Phe Leu Gln Gly Ar - #g Ala Leu Leu Asn Ala      
                   60     - #             65     - #             70            
       - - ATT GGT AAC TTG GGG CTA ACC GGA CCT TAT GC - #A GAT GCT TTA ACT AAG 
          593                                                                  
      Ile Gly Asn Leu Gly Leu Thr Gly Pro Tyr Al - #a Asp Ala Leu Thr Lys      
               75         - #         80         - #         85                
       - - CTC GGA TAC AGT TTA GAG GAT GTA GCC AGG CA - #G GAA CCG GAT GCA GCT 
          641                                                                  
      Leu Gly Tyr Ser Leu Glu Asp Val Ala Arg Gl - #n Glu Pro Asp Ala Ala      
           90             - #     95             - #    100                    
       - - TTA GGT AAT GGA GGT TTA GGA AGA CTT GCT TC - #T TGC TTT CTG GAC TCA 
          689                                                                  
      Leu Gly Asn Gly Gly Leu Gly Arg Leu Ala Se - #r Cys Phe Leu Asp Ser      
      105                 1 - #10                 1 - #15                 1 -  
     #20                                                                       
        - - ATG GCG ACA CTA AAC TAC CCT GCA TGG GGC TA - #T GGA CTT AGA TAC    
     CAA      737                                                              
       Met Ala Thr Leu Asn Tyr Pro Ala Trp Gly Ty - #r Gly Leu Arg Tyr Gln     
                      125  - #               130  - #               135        
       - - TAT GGC CTT TTC AAA CAG CTT ATT ACA AAA GA - #T GGA CAG GAG GAA GTT 
          785                                                                  
      Tyr Gly Leu Phe Lys Gln Leu Ile Thr Lys As - #p Gly Gln Glu Glu Val      
                  140      - #           145      - #           150            
       - - GCT GAA AAT TGG CTC GAG ATG GGA AAT CCA TG - #G GAA ATT GTG AGG AAT 
          833                                                                  
      Ala Glu Asn Trp Leu Glu Met Gly Asn Pro Tr - #p Glu Ile Val Arg Asn      
              155          - #       160          - #       165                
       - - GAT ATT TCG TAT CCC GTA AAA TTC TAT GGG AA - #G GTC ATT GAA GGA GCT 
          881                                                                  
      Asp Ile Ser Tyr Pro Val Lys Phe Tyr Gly Ly - #s Val Ile Glu Gly Ala      
          170              - #   175              - #   180                    
       - - GAT GGG AGG AAG GAA TGG GCT GGC GGA GAA GA - #T ATA ACT GCT GTT GCC 
          929                                                                  
      Asp Gly Arg Lys Glu Trp Ala Gly Gly Glu As - #p Ile Thr Ala Val Ala      
      185                 1 - #90                 1 - #95                 2 -  
     #00                                                                       
        - - TAT GAT GTC CCA ATA CCA GGA TAT AAA ACA AA - #A ACA ACG ATT AAC    
     CTT      977                                                              
       Tyr Asp Val Pro Ile Pro Gly Tyr Lys Thr Ly - #s Thr Thr Ile Asn Leu     
                      205  - #               210  - #               215        
       - - CGA TTG TGG ACA ACA AAG CTA GCT GCA GAA GC - #T TTT GAT TTA TAT GCT 
         1025                                                                  
      Arg Leu Trp Thr Thr Lys Leu Ala Ala Glu Al - #a Phe Asp Leu Tyr Ala      
                  220      - #           225      - #           230            
       - - TTT AAC AAT GGA GAC CAT GCC AAA GCA TAT GA - #G GCC CAG AAA AAG GCT 
         1073                                                                  
      Phe Asn Asn Gly Asp His Ala Lys Ala Tyr Gl - #u Ala Gln Lys Lys Ala      
              235          - #       240          - #       245                
       - - GAA AAG ATT TGC TAT GTC TTA TAT CCA GGT GA - #C GAA TCG CTT GAA GGA 
         1121                                                                  
      Glu Lys Ile Cys Tyr Val Leu Tyr Pro Gly As - #p Glu Ser Leu Glu Gly      
          250              - #   255              - #   260                    
       - - AAG ACG CTT AGG TTA AAG CAG CAA TAC ACA CT - #A TGT TCT GCT TCT CTT 
         1169                                                                  
      Lys Thr Leu Arg Leu Lys Gln Gln Tyr Thr Le - #u Cys Ser Ala Ser Leu      
      265                 2 - #70                 2 - #75                 2 -  
     #80                                                                       
        - - CAG GAC ATT ATT GCA CGG TTC GAG AAG AGA TC - #A GGG AAT GCA GTA    
     AAC     1217                                                              
       Gln Asp Ile Ile Ala Arg Phe Glu Lys Arg Se - #r Gly Asn Ala Val Asn     
                      285  - #               290  - #               295        
       - - TGG GAT CAG TTC CCC GAA AAG GTT GCA GTA CA - #G ATG AAT GAC ACT CAT 
         1265                                                                  
      Trp Asp Gln Phe Pro Glu Lys Val Ala Val Gl - #n Met Asn Asp Thr His      
                  300      - #           305      - #           310            
       - - CCA ACA CTT TGT ATA CCA GAA CTT TTA AGG AT - #A TTG ATG GAT GTT AAA 
         1313                                                                  
      Pro Thr Leu Cys Ile Pro Glu Leu Leu Arg Il - #e Leu Met Asp Val Lys      
              315          - #       320          - #       325                
       - - GGT TTG AGC TGG AAG CAG GCA TGG GAA ATT AC - #T CAA AGA ACG GTC GCA 
         1361                                                                  
      Gly Leu Ser Trp Lys Gln Ala Trp Glu Ile Th - #r Gln Arg Thr Val Ala      
          330              - #   335              - #   340                    
       - - TAC ACT AAC CAC ACT GTT CTA CCT GAG GCT CT - #T GAG AAA TGG AGC TTC 
         1409                                                                  
      Tyr Thr Asn His Thr Val Leu Pro Glu Ala Le - #u Glu Lys Trp Ser Phe      
      345                 3 - #50                 3 - #55                 3 -  
     #60                                                                       
        - - ACA CTT CTT GGT GAA CTG CTT CCT CGG CAC GT - #G GAG ATC ATA GCA    
     ATG     1457                                                              
       Thr Leu Leu Gly Glu Leu Leu Pro Arg His Va - #l Glu Ile Ile Ala Met     
                      365  - #               370  - #               375        
       - - ATA GAT GAG GAG CTC TTG CAT ACT ATA CTT GC - #T GAA TAT GGT ACT GAA 
         1505                                                                  
      Ile Asp Glu Glu Leu Leu His Thr Ile Leu Al - #a Glu Tyr Gly Thr Glu      
                  380      - #           385      - #           390            
       - - GAT CTT GAC TTG TTG CAA GAA AAG CTA AAC CA - #A ATG AGG ATT CTG GAT 
         1553                                                                  
      Asp Leu Asp Leu Leu Gln Glu Lys Leu Asn Gl - #n Met Arg Ile Leu Asp      
              395          - #       400          - #       405                
       - - AAT GTT GAA ATA CCA AGT TCT GTT TTG GAG TT - #G CTT ATA AAA GCC GAA 
         1601                                                                  
      Asn Val Glu Ile Pro Ser Ser Val Leu Glu Le - #u Leu Ile Lys Ala Glu      
          410              - #   415              - #   420                    
       - - GAA AGT GCT GCT GAT GTC GAA AAG GCA GCA GA - #T GAA GAA CAA GAA GAA 
         1649                                                                  
      Glu Ser Ala Ala Asp Val Glu Lys Ala Ala As - #p Glu Glu Gln Glu Glu      
      425                 4 - #30                 4 - #35                 4 -  
     #40                                                                       
        - - GAA GGT AAG GAT GAC AGT AAA GAT GAG GAA AC - #T GAG GCT GTA AAG    
     GCA     1697                                                              
       Glu Gly Lys Asp Asp Ser Lys Asp Glu Glu Th - #r Glu Ala Val Lys Ala     
                      445  - #               450  - #               455        
       - - GAA ACT ACG AAC GAA GAG GAG GAA ACT GAG GT - #T AAG AAG GTT GAG GTG 
         1745                                                                  
      Glu Thr Thr Asn Glu Glu Glu Glu Thr Glu Va - #l Lys Lys Val Glu Val      
                  460      - #           465      - #           470            
       - - GAG GAT AGT CAA GCA AAA ATA AAA CGT ATA TT - #C GGG CCA CAT CCA AAT 
         1793                                                                  
      Glu Asp Ser Gln Ala Lys Ile Lys Arg Ile Ph - #e Gly Pro His Pro Asn      
              475          - #       480          - #       485                
       - - AAA CCA CAG GTG GTT CAC ATG GCA AAT CTA TG - #T GTA GTT AGC GGG CAT 
         1841                                                                  
      Lys Pro Gln Val Val His Met Ala Asn Leu Cy - #s Val Val Ser Gly His      
          490              - #   495              - #   500                    
       - - GCA GTT AAC GGT GTT GCT GAG ATT CAT AGT GA - #A ATA GTT AAG GAT GAA 
         1889                                                                  
      Ala Val Asn Gly Val Ala Glu Ile His Ser Gl - #u Ile Val Lys Asp Glu      
      505                 5 - #10                 5 - #15                 5 -  
     #20                                                                       
        - - GTT TTC AAT GAA TTT TAC AAG TTA TGG CCA GA - #G AAA TTC CAA AAC    
     AAG     1937                                                              
       Val Phe Asn Glu Phe Tyr Lys Leu Trp Pro Gl - #u Lys Phe Gln Asn Lys     
                      525  - #               530  - #               535        
       - - ACA AAT GGT GTG ACA CCA AGA AGA TGG CTA AG - #T TTC TGT AAT CCA GAG 
         1985                                                                  
      Thr Asn Gly Val Thr Pro Arg Arg Trp Leu Se - #r Phe Cys Asn Pro Glu      
                  540      - #           545      - #           550            
       - - TTG AGT GAA ATT ATA ACC AAG TGG ACA GGA TC - #T GAT GAT TGG TTA GTA 
         2033                                                                  
      Leu Ser Glu Ile Ile Thr Lys Trp Thr Gly Se - #r Asp Asp Trp Leu Val      
              555          - #       560          - #       565                
       - - AAC ACT GAA AAA TTG GCA GAG CTT CGA AAG TT - #T GCT GAT AAC GAA GAA 
         2081                                                                  
      Asn Thr Glu Lys Leu Ala Glu Leu Arg Lys Ph - #e Ala Asp Asn Glu Glu      
          570              - #   575              - #   580                    
       - - CTC CAG TCT GAG TGG AGG AAG GCA AAA GGA AA - #T AAC AAA ATG AAG ATT 
         2129                                                                  
      Leu Gln Ser Glu Trp Arg Lys Ala Lys Gly As - #n Asn Lys Met Lys Ile      
      585                 5 - #90                 5 - #95                 6 -  
     #00                                                                       
        - - GTC TCT CTC ATT AAA GAA AAA ACA GGA TAC GT - #G GTC AGT CCC GAT    
     GCA     2177                                                              
       Val Ser Leu Ile Lys Glu Lys Thr Gly Tyr Va - #l Val Ser Pro Asp Ala     
                      605  - #               610  - #               615        
       - - ATG TTT GAT GTT CAG ATC AAG CGC ATC CAT GA - #G TAT AAA AGG CAG CTA 
         2225                                                                  
      Met Phe Asp Val Gln Ile Lys Arg Ile His Gl - #u Tyr Lys Arg Gln Leu      
                  620      - #           625      - #           630            
       - - TTA AAT ATA TTT GGA ATC GTT TAT CGC TAT AA - #G AAG ATG AAA GAA ATG 
         2273                                                                  
      Leu Asn Ile Phe Gly Ile Val Tyr Arg Tyr Ly - #s Lys Met Lys Glu Met      
              635          - #       640          - #       645                
       - - AGC CCT GAA GAA CGA AAA GAA AAG TTT GTC CC - #T CGA GTT TGC ATA TTT 
         2321                                                                  
      Ser Pro Glu Glu Arg Lys Glu Lys Phe Val Pr - #o Arg Val Cys Ile Phe      
          650              - #   655              - #   660                    
       - - GGA GGA AAA GCA TTT GCT ACA TAT GTT CAG GC - #C AAG AGA ATT GTA AAA 
         2369                                                                  
      Gly Gly Lys Ala Phe Ala Thr Tyr Val Gln Al - #a Lys Arg Ile Val Lys      
      665                 6 - #70                 6 - #75                 6 -  
     #80                                                                       
        - - TTT ATC ACT GAT GTA GGG GAA ACA GTC AAC CA - #T GAT CCC GAG ATT    
     GGT     2417                                                              
       Phe Ile Thr Asp Val Gly Glu Thr Val Asn Hi - #s Asp Pro Glu Ile Gly     
                      685  - #               690  - #               695        
       - - GAT CTT TTG AAG GTT GTA TTT GTT CCT GAT TA - #C AAT GTC AGT GTA GCA 
         2465                                                                  
      Asp Leu Leu Lys Val Val Phe Val Pro Asp Ty - #r Asn Val Ser Val Ala      
                  700      - #           705      - #           710            
       - - GAA GTG CTA ATT CCT GGT AGT GAG TTG TCC CA - #G CAT ATT AGT ACT GCT 
         2513                                                                  
      Glu Val Leu Ile Pro Gly Ser Glu Leu Ser Gl - #n His Ile Ser Thr Ala      
              715          - #       720          - #       725                
       - - GGT ATG GAG GCT AGT GGA ACC AGC AAC ATG AA - #A TTT TCA ATG AAT GGC 
         2561                                                                  
      Gly Met Glu Ala Ser Gly Thr Ser Asn Met Ly - #s Phe Ser Met Asn Gly      
          730              - #   735              - #   740                    
       - - TGC CTC CTC ATC GGG ACA TTA GAT GGT GCC AA - #T GTT GAG ATA AGA GAG 
         2609                                                                  
      Cys Leu Leu Ile Gly Thr Leu Asp Gly Ala As - #n Val Glu Ile Arg Glu      
      745                 7 - #50                 7 - #55                 7 -  
     #60                                                                       
        - - GAA GTT GGA GAG GAC AAT TTC TTT CTT TTC GG - #A GCT CAG GCT CAT    
     GAA     2657                                                              
       Glu Val Gly Glu Asp Asn Phe Phe Leu Phe Gl - #y Ala Gln Ala His Glu     
                      765  - #               770  - #               775        
       - - ATT GCT GGC CTA CGA AAG GAA AGA GCC GAG GG - #A AAG TTT GTC CCG GAC 
         2705                                                                  
      Ile Ala Gly Leu Arg Lys Glu Arg Ala Glu Gl - #y Lys Phe Val Pro Asp      
                  780      - #           785      - #           790            
       - - CCA AGA TTT GAA GAA GTA AAG GCG TTC ATT AG - #G ACA GGC GTC TTT GGC 
         2753                                                                  
      Pro Arg Phe Glu Glu Val Lys Ala Phe Ile Ar - #g Thr Gly Val Phe Gly      
              795          - #       800          - #       805                
       - - ACC TAC AAC TAT GAA GAA CTC ATG GGA TCC TT - #G GAA GGA AAC GAA GGC 
         2801                                                                  
      Thr Tyr Asn Tyr Glu Glu Leu Met Gly Ser Le - #u Glu Gly Asn Glu Gly      
          810              - #   815              - #   820                    
       - - TAT GGT CGT GCT GAC TAT TTT CTT GTA GGA AA - #G GAT TTC CCC GAT TAT 
         2849                                                                  
      Tyr Gly Arg Ala Asp Tyr Phe Leu Val Gly Ly - #s Asp Phe Pro Asp Tyr      
      825                 8 - #30                 8 - #35                 8 -  
     #40                                                                       
        - - ATA GAG TGC CAA GAT AAA GTT GAT GAA GCA TA - #T CGA GAC CAG AAG    
     AAA     2897                                                              
       Ile Glu Cys Gln Asp Lys Val Asp Glu Ala Ty - #r Arg Asp Gln Lys Lys     
                      845  - #               850  - #               855        
       - - TGG ACC AAA ATG TCG ATC TTA AAC ACA GCT GG - #A TCG TTC AAA TTT AGC 
         2945                                                                  
      Trp Thr Lys Met Ser Ile Leu Asn Thr Ala Gl - #y Ser Phe Lys Phe Ser      
                  860      - #           865      - #           870            
       - - AGT GAT CGA ACA ATT CAT CAA TAT GCA AGA GA - #T ATA TGG AGA ATT GAA 
         2993                                                                  
      Ser Asp Arg Thr Ile His Gln Tyr Ala Arg As - #p Ile Trp Arg Ile Glu      
              875          - #       880          - #       885                
       - - CCT GTT GAA TTA CCT TAA AAGTTAGCCA GTTAAAGGAT GA - #AAGCCAAT        
         3041                                                                  
      Pro Val Glu Leu Pro  *                                                   
          890                                                                  
       - - TTTTTCCCCC TGAGGTTCTC CCATACTGTT TATTAGTACA TATATTGTCA AT -         
     #TGTTGCTA   3101                                                          
        - - CTGAAATGAT AGAAGTTTTG AATATTTACT GTCAATAAAA TACAGTTGAT TC -        
     #CATTTGAA   3161                                                          
        - - AAAAAAAAAA                - #                  - #                 
      - #      3171                                                            
       - -  - - (2) INFORMATION FOR SEQ ID NO:6:                               
       - -      (i) SEQUENCE CHARACTERISTICS:                                  
                (A) LENGTH:  974 ami - #no acids                               
                (B) TYPE: amino acid                                           
                (D) TOPOLOGY: linear                                           
       - -     (ii) MOLECULE TYPE: protein                                     
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:                         
       - - Met Ala Thr Phe Ala Val Ser Gly Leu Asn Se - #r Ile Ser Ser Ile Ser 
     81 -80                - # -75                - # -70                      
       - - Ser Phe Asn Asn Asn Phe Arg Ser Lys Asn Se - #r Asn Ile Leu Leu Ser 
     65                 - - #60                 - - #55                 - -    
     #50                                                                       
        - - Arg Arg Arg Ile Leu Leu Phe Ser Phe Arg Ar - #g Arg Arg Arg Ser    
     Phe                                                                       
                       -45  - #               -40  - #               -35       
       - - Ser Val Ser Ser Val Ala Ser Asp Gln Lys Gl - #n Lys Thr Lys Asp Ser 
                  -30      - #           -25      - #           -20            
       - - Ser Ser Asp Glu Gly Phe Thr Leu Asp Val Ph - #e Gln Pro Asp Ser Thr 
              -15          - #       -10          - #        -5                
       - - Ser Val Leu Ser Ser Ile Lys Tyr His Ala Gl - #u Phe Thr Pro Ser Phe 
            1            - #   5               - #   10               - #   15 
       - - Ser Pro Glu Lys Phe Glu Leu Pro Lys Ala Ty - #r Tyr Ala Thr Ala Glu 
                       20 - #                 25 - #                 30        
       - - Ser Val Arg Asp Thr Leu Ile Ile Asn Trp As - #n Ala Thr Tyr Glu Phe 
                   35     - #             40     - #             45            
       - - Tyr Glu Lys Met Asn Val Lys Gln Ala Tyr Ty - #r Leu Ser Met Glu Phe 
               50         - #         55         - #         60                
       - - Leu Gln Gly Arg Ala Leu Leu Asn Ala Ile Gl - #y Asn Leu Gly Leu Thr 
           65             - #     70             - #     75                    
       - - Gly Pro Tyr Ala Asp Ala Leu Thr Lys Leu Gl - #y Tyr Ser Leu Glu Asp 
       80                 - # 85                 - # 90                 - # 95 
       - - Val Ala Arg Gln Glu Pro Asp Ala Ala Leu Gl - #y Asn Gly Gly Leu Gly 
                      100  - #               105  - #               110        
       - - Arg Leu Ala Ser Cys Phe Leu Asp Ser Met Al - #a Thr Leu Asn Tyr Pro 
                  115      - #           120      - #           125            
       - - Ala Trp Gly Tyr Gly Leu Arg Tyr Gln Tyr Gl - #y Leu Phe Lys Gln Leu 
              130          - #       135          - #       140                
       - - Ile Thr Lys Asp Gly Gln Glu Glu Val Ala Gl - #u Asn Trp Leu Glu Met 
          145              - #   150              - #   155                    
       - - Gly Asn Pro Trp Glu Ile Val Arg Asn Asp Il - #e Ser Tyr Pro Val Lys 
      160                 1 - #65                 1 - #70                 1 -  
     #75                                                                       
        - - Phe Tyr Gly Lys Val Ile Glu Gly Ala Asp Gl - #y Arg Lys Glu Trp    
     Ala                                                                       
                       180  - #               185  - #               190       
       - - Gly Gly Glu Asp Ile Thr Ala Val Ala Tyr As - #p Val Pro Ile Pro Gly 
                  195      - #           200      - #           205            
       - - Tyr Lys Thr Lys Thr Thr Ile Asn Leu Arg Le - #u Trp Thr Thr Lys Leu 
              210          - #       215          - #       220                
       - - Ala Ala Glu Ala Phe Asp Leu Tyr Ala Phe As - #n Asn Gly Asp His Ala 
          225              - #   230              - #   235                    
       - - Lys Ala Tyr Glu Ala Gln Lys Lys Ala Glu Ly - #s Ile Cys Tyr Val Leu 
      240                 2 - #45                 2 - #50                 2 -  
     #55                                                                       
        - - Tyr Pro Gly Asp Glu Ser Leu Glu Gly Lys Th - #r Leu Arg Leu Lys    
     Gln                                                                       
                       260  - #               265  - #               270       
       - - Gln Tyr Thr Leu Cys Ser Ala Ser Leu Gln As - #p Ile Ile Ala Arg Phe 
                  275      - #           280      - #           285            
       - - Glu Lys Arg Ser Gly Asn Ala Val Asn Trp As - #p Gln Phe Pro Glu Lys 
              290          - #       295          - #       300                
       - - Val Ala Val Gln Met Asn Asp Thr His Pro Th - #r Leu Cys Ile Pro Glu 
          305              - #   310              - #   315                    
       - - Leu Leu Arg Ile Leu Met Asp Val Lys Gly Le - #u Ser Trp Lys Gln Ala 
      320                 3 - #25                 3 - #30                 3 -  
     #35                                                                       
        - - Trp Glu Ile Thr Gln Arg Thr Val Ala Tyr Th - #r Asn His Thr Val    
     Leu                                                                       
                       340  - #               345  - #               350       
       - - Pro Glu Ala Leu Glu Lys Trp Ser Phe Thr Le - #u Leu Gly Glu Leu Leu 
                  355      - #           360      - #           365            
       - - Pro Arg His Val Glu Ile Ile Ala Met Ile As - #p Glu Glu Leu Leu His 
              370          - #       375          - #       380                
       - - Thr Ile Leu Ala Glu Tyr Gly Thr Glu Asp Le - #u Asp Leu Leu Gln Glu 
          385              - #   390              - #   395                    
       - - Lys Leu Asn Gln Met Arg Ile Leu Asp Asn Va - #l Glu Ile Pro Ser Ser 
      400                 4 - #05                 4 - #10                 4 -  
     #15                                                                       
        - - Val Leu Glu Leu Leu Ile Lys Ala Glu Glu Se - #r Ala Ala Asp Val    
     Glu                                                                       
                       420  - #               425  - #               430       
       - - Lys Ala Ala Asp Glu Glu Gln Glu Glu Glu Gl - #y Lys Asp Asp Ser Lys 
                  435      - #           440      - #           445            
       - - Asp Glu Glu Thr Glu Ala Val Lys Ala Glu Th - #r Thr Asn Glu Glu Glu 
              450          - #       455          - #       460                
       - - Glu Thr Glu Val Lys Lys Val Glu Val Glu As - #p Ser Gln Ala Lys Ile 
          465              - #   470              - #   475                    
       - - Lys Arg Ile Phe Gly Pro His Pro Asn Lys Pr - #o Gln Val Val His Met 
      480                 4 - #85                 4 - #90                 4 -  
     #95                                                                       
        - - Ala Asn Leu Cys Val Val Ser Gly His Ala Va - #l Asn Gly Val Ala    
     Glu                                                                       
                       500  - #               505  - #               510       
       - - Ile His Ser Glu Ile Val Lys Asp Glu Val Ph - #e Asn Glu Phe Tyr Lys 
                  515      - #           520      - #           525            
       - - Leu Trp Pro Glu Lys Phe Gln Asn Lys Thr As - #n Gly Val Thr Pro Arg 
              530          - #       535          - #       540                
       - - Arg Trp Leu Ser Phe Cys Asn Pro Glu Leu Se - #r Glu Ile Ile Thr Lys 
          545              - #   550              - #   555                    
       - - Trp Thr Gly Ser Asp Asp Trp Leu Val Asn Th - #r Glu Lys Leu Ala Glu 
      560                 5 - #65                 5 - #70                 5 -  
     #75                                                                       
        - - Leu Arg Lys Phe Ala Asp Asn Glu Glu Leu Gl - #n Ser Glu Trp Arg    
     Lys                                                                       
                       580  - #               585  - #               590       
       - - Ala Lys Gly Asn Asn Lys Met Lys Ile Val Se - #r Leu Ile Lys Glu Lys 
                  595      - #           600      - #           605            
       - - Thr Gly Tyr Val Val Ser Pro Asp Ala Met Ph - #e Asp Val Gln Ile Lys 
              610          - #       615          - #       620                
       - - Arg Ile His Glu Tyr Lys Arg Gln Leu Leu As - #n Ile Phe Gly Ile Val 
          625              - #   630              - #   635                    
       - - Tyr Arg Tyr Lys Lys Met Lys Glu Met Ser Pr - #o Glu Glu Arg Lys Glu 
      640                 6 - #45                 6 - #50                 6 -  
     #55                                                                       
        - - Lys Phe Val Pro Arg Val Cys Ile Phe Gly Gl - #y Lys Ala Phe Ala    
     Thr                                                                       
                       660  - #               665  - #               670       
       - - Tyr Val Gln Ala Lys Arg Ile Val Lys Phe Il - #e Thr Asp Val Gly Glu 
                  675      - #           680      - #           685            
       - - Thr Val Asn His Asp Pro Glu Ile Gly Asp Le - #u Leu Lys Val Val Phe 
              690          - #       695          - #       700                
       - - Val Pro Asp Tyr Asn Val Ser Val Ala Glu Va - #l Leu Ile Pro Gly Ser 
          705              - #   710              - #   715                    
       - - Glu Leu Ser Gln His Ile Ser Thr Ala Gly Me - #t Glu Ala Ser Gly Thr 
      720                 7 - #25                 7 - #30                 7 -  
     #35                                                                       
        - - Ser Asn Met Lys Phe Ser Met Asn Gly Cys Le - #u Leu Ile Gly Thr    
     Leu                                                                       
                       740  - #               745  - #               750       
       - - Asp Gly Ala Asn Val Glu Ile Arg Glu Glu Va - #l Gly Glu Asp Asn Phe 
                  755      - #           760      - #           765            
       - - Phe Leu Phe Gly Ala Gln Ala His Glu Ile Al - #a Gly Leu Arg Lys Glu 
              770          - #       775          - #       780                
       - - Arg Ala Glu Gly Lys Phe Val Pro Asp Pro Ar - #g Phe Glu Glu Val Lys 
          785              - #   790              - #   795                    
       - - Ala Phe Ile Arg Thr Gly Val Phe Gly Thr Ty - #r Asn Tyr Glu Glu Leu 
      800                 8 - #05                 8 - #10                 8 -  
     #15                                                                       
        - - Met Gly Ser Leu Glu Gly Asn Glu Gly Tyr Gl - #y Arg Ala Asp Tyr    
     Phe                                                                       
                       820  - #               825  - #               830       
       - - Leu Val Gly Lys Asp Phe Pro Asp Tyr Ile Gl - #u Cys Gln Asp Lys Val 
                  835      - #           840      - #           845            
       - - Asp Glu Ala Tyr Arg Asp Gln Lys Lys Trp Th - #r Lys Met Ser Ile Leu 
              850          - #       855          - #       860                
       - - Asn Thr Ala Gly Ser Phe Lys Phe Ser Ser As - #p Arg Thr Ile His Gln 
          865              - #   870              - #   875                    
       - - Tyr Ala Arg Asp Ile Trp Arg Ile Glu Pro Va - #l Glu Leu Pro         
      880                 8 - #85                 8 - #90                      
       - -  - - (2) INFORMATION FOR SEQ ID NO:7:                               
       - -      (i) SEQUENCE CHARACTERISTICS:                                  
                (A) LENGTH: 27 base - #pairs                                   
                (B) TYPE: nucleic acid                                         
                (C) STRANDEDNESS: single                                       
                (D) TOPOLOGY: linear                                           
       - -     (ii) MOLECULE TYPE: DNA (genomic)                               
       - -    (iii) HYPOTHETICAL: NO                                           
       - -     (iv) ANTI-SENSE: NO                                             
       - -      (v) FRAGMENT TYPE: internal                                    
       - -     (vi) ORIGINAL SOURCE:                                           
                (A) ORGANISM: Solanum t - #uberosum                            
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: misc.sub.-- - #feature                           
                (B) LOCATION: 1..27                                            
                (D) OTHER INFORMATION: - #/function= "primer"                  
                     /label= - #SPL1                                           
       - -      (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #7:                    
       - - ATTCGAAAAG CTCGAGATTT GCATAGA          - #                  - #     
             27                                                                
       - -  - - (2) INFORMATION FOR SEQ ID NO:8:                               
       - -      (i) SEQUENCE CHARACTERISTICS:                                  
                (A) LENGTH: 27 base - #pairs                                   
                (B) TYPE: nucleic acid                                         
                (C) STRANDEDNESS: single                                       
                (D) TOPOLOGY: linear                                           
       - -     (ii) MOLECULE TYPE: DNA (genomic)                               
       - -    (iii) HYPOTHETICAL: NO                                           
       - -     (iv) ANTI-SENSE: NO                                             
       - -      (v) FRAGMENT TYPE: internal                                    
       - -     (vi) ORIGINAL SOURCE:                                           
                (A) ORGANISM: Solanum t - #uberosum                            
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: misc.sub.-- - #feature                           
                (B) LOCATION: 1..27                                            
                (D) OTHER INFORMATION: - #/function= "primer"                  
                     /label= - #SPL2                                           
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:                         
       - - GTTTATTTTC CATCGATGGA AGGTGGT          - #                  - #     
             27                                                                
       - -  - - (2) INFORMATION FOR SEQ ID NO:9:                               
       - -      (i) SEQUENCE CHARACTERISTICS:                                  
                (A) LENGTH: 23 base - #pairs                                   
                (B) TYPE: nucleic acid                                         
                (C) STRANDEDNESS: single                                       
                (D) TOPOLOGY: linear                                           
       - -     (ii) MOLECULE TYPE: DNA (genomic)                               
       - -    (iii) HYPOTHETICAL: NO                                           
       - -     (iv) ANTI-SENSE: NO                                             
       - -      (v) FRAGMENT TYPE: internal                                    
       - -     (vi) ORIGINAL SOURCE:                                           
                (A) ORGANISM: Solanum t - #uberosum                            
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: misc.sub.-- - #feature                           
                (B) LOCATION: 1..23                                            
                (D) OTHER INFORMATION: - #/function= "primer"                  
                     /label= - #SPH1                                           
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:                         
       - - GTGTGCTCTC GAGCATTGAA AGC           - #                  - #        
             23                                                                
       - -  - - (2) INFORMATION FOR SEQ ID NO:10:                              
       - -      (i) SEQUENCE CHARACTERISTICS:                                  
                (A) LENGTH: 25 base - #pairs                                   
                (B) TYPE: nucleic acid                                         
                (C) STRANDEDNESS: single                                       
                (D) TOPOLOGY: linear                                           
       - -     (ii) MOLECULE TYPE: DNA (genomic)                               
       - -    (iii) HYPOTHETICAL: NO                                           
       - -     (iv) ANTI-SENSE: NO                                             
       - -      (v) FRAGMENT TYPE: internal                                    
       - -     (vi) ORIGINAL SOURCE:                                           
                (A) ORGANISM: Solanum t - #uberosum                            
       - -     (ix) FEATURE:                                                   
                (A) NAME/KEY: misc.sub.-- - #feature                           
                (B) LOCATION: 1..25                                            
                (D) OTHER INFORMATION: - #/function= "primer"                  
                     /label= - #SPH2                                           
       - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:                        
       - - ATAATATCCT GAATCGATGC ACTGC          - #                  - #       
             25                                                                
     __________________________________________________________________________

Claims

1. A potato plant having improved cold-storage characteristics, comprising a potato plant transformed with an expression cassette having a plant promoter sequence operably linked to a DNA sequence comprising at least 20 nucleotides of a gene encoding an.alpha. glucan phosphorylase selected from the group consisting of.alpha. glucan L-type tuber phosphorylase (GLTP) and.alpha. glucan H-type phosphorylase (GHTP).

2. The potato plant of claim 1, wherein the encoded.alpha. glucan phosphorylase is GLTP.

3. The potato plant of claim 1, wherein the encoded.alpha. glucan phosphorylase is GHTP.

4. The potato plant of claim 1, wherein the DNA sequence comprises nucleotides 338 to 993 of SEQ ID NO: 1.

5. The potato plant of claim 1, wherein the DNA sequence comprises nucleotides 147 to 799 of SEQ ID NO: 3.

6. The potato plant of any one of claims 1, 2, 3, 4 or 5, wherein the DNA sequence is linked to the promoter sequence in an antisense orientation.

7. The potato plant of claim 2, wherein the sum of the concentration of glucose and fructose in tubers of the plant measured at harvest is at least 10% lower than the sum of the concentration of glucose and fructose in tubers of an untransformed plant measured at harvest.

8. The potato plant of claim 2, wherein the sum of the concentration of glucose and fructose in tubers of the plant measured at harvest is at least 30% lower than the sum of the concentration of glucose and fructose in tubers of an untransformed plant measured at harvest.

9. The potato plant of claim 2, wherein the sum of the concentration of glucose and fructose in tubers of the plant measured at harvest is at least 80% lower than the sum of the concentration of glucose and fructose in tubers of an untransformed plant measured at harvest.

10. The potato plant of claim 2, wherein the sum of the concentration of glucose and fructose in tubers of the plant stored at 4.degree. C. for about three months is at least 10% lower than the sum of the concentration of glucose and fructose in tubers of an untransformed plant stored under the same conditions.

11. The potato plant of claim 2, wherein the sum of the concentration of glucose and fructose in tubers of the plant stored at 4.degree. C. for about three months is at least 30% lower than the sum of the concentration of glucose and fructose in tubers of an untransformed plant stored under the same conditions.

12. The potato plant of claim 2, wherein the sum of the concentration of glucose and fructose in tubers of the plant stored at 4.degree. C. for about three months is at least 39% lower than the sum of the concentration of glucose and fructose in tubers of an untransformed plant stored under the same conditions.

13. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 proteins.sup.-1 h.sup.-1 in tubers of the plant measured at harvest is at least 10% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant measured at harvest.

14. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant measured at harvest is at least 30% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant measured at harvest.

15. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant measured at harvest is at least 66% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant measured at harvest.

16. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. for about three months is at least 10% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

17. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 proteins h.sup.-1 in tubers of the plant stored at 4.degree. C. for about three months is at least 30% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

18. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. for about three months is at least 70% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

19. The potato plant of claim 3, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. for about three months is at least 10% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

20. The potato plant of claim 3, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. Fop about three months is at least 28% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

21. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. for about six months is at least 10% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

22. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.- protein.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. for about six months is at least 30% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

23. The potato plant of claim 2, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. for about six months is at least 69% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

24. The potato plant of claim 3, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 protein.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. for about six months is at least 10% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

25. The potato plant of claim 3, wherein the total.alpha. glucan phosphorylase activity measured as.mu.mol NADPH produced mg.sup.-1 proteins.sup.-1 h.sup.-1 in tubers of the plant stored at 4.degree. C. for about six months is at least 39% lower than the total.alpha. glucan phosphorylase activity in tubers of an untransformed plant stored under the same conditions.

26. The potato plant of claim 2, wherein a chip score for tubers of the plant measured at harvest is at least 5% higher than the chip scores for tubers of an untransformed plant measured at harvest.

27. The potato plant of claim 2, wherein a chip score for tubers of the plant measured at harvest is at least 30% higher than the chip scores for tubers of an untransformed plant measured at harvest.

28. The potato plant of claim 2, wherein a chip score for tubers of the plant measured at harvest is at least 46% higher than the chip scores for tubers of an untransformed plant measured at harvest.

29. The potato plant of claim 3, wherein a chip score for tubers of the plant measured at harvest is at least 5% higher than the chip scores for tubers of an untransformed plant measured at harvest.

30. The potato plant of claim 3, wherein a chip score for tubers of the plant measured at harvest is at least 10% higher than the chip scores for tubers of an untransformed plant measured at harvest.

31. The potato plant of claim 2, wherein a chip score for tubers of the plant stored at 4.degree. C. for about three months is at least 5% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

32. The potato plant of claim 2, wherein a chip score for tubers of the plant stored at 4.degree. C. for about three months is at least 30% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

33. The potato plant of claim 2, wherein a chip score for tubers of the plant stored at 4.degree. C. for about three months is at least 89% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

34. The potato plant of claim 3, wherein a chip score for tubers of the plant stored at 4.degree. C. for about three months is at least 5% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

35. The potato plant of claim 3, wherein a chip score for tubers of the plant stored at 4.degree. C. for about three months is at least 10% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

36. The potato plant of claim 2, wherein a chip score for tubers of the plant stored at 4.degree. C. for about four months is at least 5% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

37. The potato plant of claim 2, wherein a chip score for tubers of the plant stored at 4.degree. C. for about four months is at least 30% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

38. The potato plant of claim 2, wherein a chip score for tubers of the plant stored at 4.degree. C. for about four months is at least 89% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

39. The potato plant of claim 3, wherein a chip score for tubers of the plant stored at 4.degree. C. for about four months is at least 5% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

40. The potato plant of claim 3, wherein a chip score for tubers of the plant stored at 4.degree. C. for about four months is at least 25% higher than the chip scores for tubers of an untransformed plant stored under the same conditions.

41. A method for improving the cold-storage characteristics of a potato tuber, comprising:

introducing into a potato plant an expression cassette having a plant promoter sequence operably linked to a DNA sequence comprising at least 20 nucleotides of a gene encoding an.alpha. glucan phosphorylase selected from the group consisting of GLTP and GHTP.

42. The method of claim 41, wherein the encoded.alpha. glucan phosphorylase is GLTP.

43. The method of claim 41, wherein the encoded.alpha. glucan phosphorylase is GHTP.

44. The method of claim 41, wherein the DNA sequence comprises nucleotides 338 to 993 of SEQ ID. NO: 1.

45. The method of claim 41, wherein the DNA sequence comprises nucleotides 147 to 799 of SEQ ID. NO: 3.

46. The method of any one of claims 41, 42, 43, 44 or 45 wherein the DNA sequence is linked to the promoter sequence in an antisense orientation.

47. The potato plant of claim 1, wherein the encoded.alpha. glucan phosphorylase comprises an amino acid sequence depicted in SEQ ID NO:2.

48. The potato plant of claim 1, wherein the DNA sequence comprises at least 20 nucleotides of the gene encoding.alpha. glucan phosphorylase as depicted in SEQ ID NO:1.

49. The potato plant of claim 1, wherein the encoded.alpha. glucan phosphorylase comprises an amino acid sequence depicted in SEQ ID NO:4.

50. The potato plant of claim 1, wherein the DNA sequence comprises at least 20 nucleotides of the gene encoding an.alpha. glucan phosphorylase as depicted in SEQ ID NO:3.

51. The method of claim 41, wherein the encoded.alpha. glucan phosphorylase comprises an animo acid sequence depicted in SEQ ID NO:2.

52. The method of claim 41, wherein the DNA sequence comprises at least 20 nucleotides of the gene encoding an.alpha. glucan phosphotylase as depicted in SEQ ID NO:1.

53. The method of claim 41, wherein the encoded.alpha. glucan phosphorylase comprises an amino acid sequence depicted in SEQ ID NO:4.

54. The method of claim 41, wherein the DNA sequence comprises at least 20 nucleotides of the gene encoding an.alpha. glucan phosphorylase as depicted in SEQ ID NO:3.